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Association for 
Information and Image 
Management 



Centimetei 














lomaoCX £dl&oru ( \hipeM> 


A SELECTIVE MICROFILM EDITION 

PART II 
( 1879 - 1886 ) 


Thomas E. Jeffrey 

Microfilm Editor and Associate Director 

Paul B. Israel 
Assistant Editor 


Mary Ann Hellrigel Douglas G. Tarr 

David W. Hutchings Robert A. Rosenberg 

Editorial Associates 


Leonard DeGraaf 
Joseph P. Sullivan 
Alan Stein 
Karen Kozak 


Keith A. Nier 
Assistant Editor 

Reese V. Jenkins 
Director and Editor 


John Deasey 
Barbara B. Tomblln 
Jacquelyn Miller 
Marla Antonakakls 


Sponsors 

Rutgers, The State University of New Jersey 
National Park Service, Edison National Historic Site 
New Jersey Historical Commission 

Smithsonian Institution 


University Publications of America 
Frederick, Maryland 
1987 

















BOARD OF SPONSORS 


Rutgers, The State University of 
New Jersey 

Edward J. Bloustcin 
T, Alexander Pond 
Tilden G. Edelstein 
John Gillis 

New Jersey Historical Commission 
Bernard Bush 
Howard L. Green 


National Park Service, Edison 
National Historic Site 
Roy W. Weaver 
Edward J. Pcrshey 
Smithsonian Institution 
Bernard Finn 
Arthur P. Moiella 


EDITORIAL ADVISORY BOARD 

James Brittain, Georgia Institute of Technology 
Alfred D. Chandler, Jr., Harvard University 
Neil Harris, University of Chicago 
Thomas Parke Hughes, University of Pennsylvania 
Arthur Link, Princeton University 
Nathan Reingold, Smithsonian Institution 
Robert E. Schofield, Iowa State University 


CORPORATE ASSOCIATES 

William C. Hittinger (chairman), RCA Corporation 
Edward J. Bloustein, Rutgers, The State University of N.J. 
Cees Bruynes, North American Philips Corporation 
Paul J. Christiansen, Charles Edison Fund 
Philip F. Dietz, Westinghouse Electric Corporation 
Roland W. Schmitt, General Electric Corporation 
Harold W. Sonn, Public Service Electric and Gas Company 
Morris Tanenbaum, AT&T 








THOMAS A. EDISON PAPERS 


Reese V. Jenkins 
Director and Editor 

Thomas E. Jeffrey 

Associate Director and Microfilm Editor 










FINANCIAL CONTRIBUTORS 


PRIVATE FOUNDATIONS 
Alfred P. Sloan Poundation 
Charles Edison Fund 
The Hyde and Watson Foundation 
Geraldine R. Dodge Foundation 


PUBLIC FOUNDATIONS 

National Science Foundation 
National Endowment for the Humanities 


PRIVATE CORPORATIONS AND INDIVIDUALS 


Alabama Power Company 
Amerada Hess Corporation 
AT&T 

Atlantic Electric 

Association of Edison Illuminating 
Companies 

I!attellc Memorial Institute Foundation 
The Boston Edison Foundation 
Cabot Corporation Foundation 
Carolina Power and Light Company 
Consolidated Edison Company of 
New York, Inc. 

Consumers Power Company 
Corning Glass Works Foundation 
Duke Power Company 
Exxon Corporation 
Florida Power & Light Company 
General Electric Foundation 
Gould Inc. Foundation 
Gulf States Utilities Company 
Idaho Power Company 
International Brotherhood of Electrical 
Workers 

Iowa Power and Light Company 


Mr. and Mrs. Stanley H. Katz 
Matsushita Electric Industrial Co., Ltd. 
McGraw-Edison Company 
Middle South Services, Inc. 

Minnesota Power 

New Jersey Bell Telephone Company 
New York State Electric & Gas 
Corporation 

North American Philips Corporation 
Philadelphia Electric Company 
Philips International B.V. 

Public Service Electric and Gas 
Company 
RCA Corporation 
Robert Bosch GmbH 
San Diego Gas & Electric 
Savannah Electric and Power Company 
Schering Plough Foundation 
Texas Utilities Company 
Thomson-Brandt 
Transamcrica Delaval Inc. 

Westinghouse Educational Foundation 
Wisconsin Public Service 
Corporation 
















A Note on the Sources 

The pages which have been 
filmed are the best copies 
available. Every technical 
effort possible has been 
made to ensure legibility. 













THOMAS A. EDISON PAPERS 


A SELECTIVE MICROFILM EDITION 
PARTH 
(1879-1886) 


REEL 92 


SPECIAL COLLECTIONS SERIES (SPC-3) 


Charles Batchelor Collection 
Patents 

Unbound Documents 






CHARLES BATCHELOR PATENTS, 1869-1880 


Included in this series is one volume of Edison's British patents from the years 
1872-1880 (Cat. 1321) and one volume of Edison's U.S. patents from the years 1869- 
1879 (Cat. 1320). Only the British patents have been filmed. The Batchelor 
Collection also contains numerous unbound patents issued to Edison, Batchelor, and 
other inventors. A complete set of Edison's U.S. patents can be found in Thomas 
A. Edison Papers Microfilm Edison, Part I, reels 1-2. 








Edison's British Patents, Cat. 1321 


This book covers the years 1872-1880 and contains printed copies of British 
patents issued to Edison. The patents relate to several inventions, including 
printing, automatic, and multiplex telegraphs; the electric pen and autographic 
press; the telephone; electric lighting; and polyform. All of the patents are 
complete as issued by the British Patent Office. Many are accompanied by 
drawings. A few of the patents appear in the form of provisional specifications. A 
provisional specification in the British patent system was similar to the caveat in 
the U.S. patent system. It protected the inventor for a period of time prior to the 
filing of a full specification. The description of the invention and the statement of 
claims were generally less detailed in a provisional specification than in a full 
specification. The spine of the book is stamped "Edison's British Patents 1872- 
1880." 




A.D. 1872, 13 th May. N" 1453. 


Printing Telegraphs. 


LETTERS PATENT to Thomas Alva Edison, of Newark, in the State 
of New Jersey, United Statos of America, for tho Invention of 
“ Jmpbovemehts nr Pbihtisq Teleqbaphs.” 

Sealed tlio 24th September 1872, and dnted tho 18th May 1872. 


PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at 
tho Office of the Commissioners of Patents, with his Petition, on 
the 13th May 1872. 

I, Thomas Alva Edison, of Newark, in tho State of New Jersey, 
5 United States of America, do hereby doclaro tho nature of tho said In¬ 
vention for “ Impbovemehts nr Phihtiho Teieobaphs,” to bo as follows 

These improvements relate to tho mechanism for moving tho sovcral 
typo wheels of different printing telegraphs in unison, and giving tho 
impression. 

10 Tho type wheel is mounted upon a shaft, and revolved by a step-by¬ 
stop motion by a lover and armature acted upon by an cicctro-magnot, 
tho core of which is grooved upon one side longitudinally, which I find 






2 A.D. 1872.—N° 1453. 

__ Edison' s Improvements in Printing Telegraphs. 

is preferable iu printing telegraphs, because greater speed can be 
obtained. 

"Whore two lino wires aro used, ono to the typo-wheel magnet, the 
other to the printing magnet, tho ratchet whcol of the step-by-step 
movement lias half as many teeth as there aro types and spaces on tho 5 
type wheel, and one letter is printed on the open circuit and tho next on 
the closed circuit, and this typo wheel is on a slcovo and moved by a 
lever acted on by the printing lover. Tho type wheel can bo turned 
around tho extent of one letter, so as to print the alternate letters that 
had previously been out of position for printing. This samo turning 10 
movement of the typo wheel on its shaft is sometimes communicated 
by a V shaped wedge and holding dog, acted upon by the printing lover. 

Tho type wheels aro stopped at unison by the continued rotation of 
tho type wheel bringing an arm into the patli of a stop on tho lypc- 
wliccl shaft, and this is liberated by operating tho printing lever. 15 

In cases where the unison can bo operated most conveniently by tho 
printing lever, it is effected by a wedge thereon acting against inclined 
teeth on a wheel upon tho type-wheel shaft. Tho absence of ono tooth 
in this wheel prevents tho further action of tho wedge at the unison 
point. 2Q 

The printing lever is provided with a weight that prevents it being 
easily moved by the electro-magnet, but when moved its inertia offccts 
the impression. This can be used on one lino wiro instruments, tho 
impression being given after tho typo wheel is set by keeping tho circuit 
closed. An air cylinder with a piston also is employed to provont tho 25 
printing lover moving, except by keeping tho circuit closed a sufficient " 
time. 

The paper is drawn along by a swinging claw or tooth pressed upon 
the. paper by a toggle or spring, and then moving with a swinging 
segment or a roller, and a holding pawl keeps tho paper from drawing 80 
back. 

Where two typo wheels are used, and an end movement is given upon 
tho shaft to bring one into action and remove tho other from action, tho 
said end movement is given either by an electro-magnct and polarized 
armature that will be held in contact with the cores or repelled according 35 
to tho polarity of tho current, or tho printing may bo from ono typo 


Specification. A.D. 1872.—N° 1453. 3 

_ Edison's Improvements in Printing Tele graphs. ~ 

wheel with an open circuit and from tho other with a closed circuit or 
clso the endwise movement is given from [the printing lever by lever or 
wedge acting connections operating upon radially slotted wheels. 

It is to be understood that tho printing instruments before described 
5 arc located at tho places or stations distant from tho sending or trans¬ 
mitting station, and that they aro operated by electric pulsations given 
from the said transmitting station. I now describe tho pulsator to bo 
used at said transmitting station to send these electric pulsations :-A 
motor mndc of a shaft and armnturo revolved by stationaiy electro- 
10 magnets gives motion by a friction clutch to a circuit breaker made of 
alternate conducting and non-conducting material. Tho typo wheel at 
the distant station is moved around by these pulsations in unison with 
a revolving arm at tho transmitter (actuated by gearing from tho pul- 
sator), and when this arm is stopped by depressing one of a range of 
15 finger keys the pulsator is stopped, also the typo wheel, and the printing 
circuit brought into action. The speed of the pulsator shaft is regulated 
by a governor, that acts as a circuit breaker to the electro-magnets of tho 
motor, or “ cuts out” those magnets by closing a shunt or more direct 
circuit. 

20 Where many printing telegraphs are worked in several circuits by one 
transmitter or pulsator, it is often preferable to employ short relay 
magnets with slotted cores and relay circuits between the transmitting 
and printing instruments. ° 


SPECIFICATION filed in pursuance of tho conditions of tho Letters 
25 Patent, and of an Order of tho Lord Chancellor, by the said 
Ihornns Alva Edison in tho Great Seal Patent Offico on the loth 
November 1872. 

TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Thomas 
Aiva Edison, of Newark, in the State of Now Jersey, United States of 
30 America, send greeting. 

WHEREAS Her most Excellent Majesty Queen Victoria, by ner 
Letters Patent, bearing date the Thirteenth day of May, in tho year of 
our Lord Ono thousand eight hundred and seventy-two, in the thirty. 
I'tth year of Her reign, did, for Herself, Her heirs and successors, give 








4 A.D. 1872.—N° 1453. sp«m»«on. 

Edison's Improvements in Printing Telegraphs. 
and grant unto rao, the said Thomas Alva Edison, Her special licenco 
that I, tho said Thomas Alva Edison, my executors, administrators, and 
assigns, or such others as I, tho said Thomas Alva Edison, my executors, 
administrators, and assigns, should at any time agree with, and no others,, 
from time to timo and at all times thereafter during tho term therein 5 
expressed, should and lawfully might mako, use, oxerciso, and vend, 
within tho United Kingdom of Great Britain and Ireland, tho Channel 
Islands, and Isle of Man, an Invention for “ Improvehehts a Prixtiho 
Telegraphs,” upon tho condition (amongst others) that I, tho said Thomas 
Alva Edison, my executors or administrators, by an instrument in writing 10 
under my, or their, or one of their hands and seals, should particularly 
describo and ascertain tho nature of tho said Invention, and in wliat 
manner tho same was to bo performed, and cause tho same to bo filed 
in the Great Seal Patent Office within six calendar months next and 
immediately after tho date of the said Letters Patent. 15 

NOW KNOW YE, that I, tho said Thomas Alva Edison, do hereby 
declare tlio naturo of my said Invention, and in what manner tho same 
is to be performed, to bo particularly described and ascertained in and 
by the following statement, reference being made to tho Drawings 
hereunto annexed, and to tho letters and figures marked thereon (that is 20 
to say) 

My improvements comprise a system of reporting from one central 
point to any number of distant points the quotations of market values, 
gold, stocks, and other articles of trade or merchandize. 

Tho first part of this improvement rointes to a machine that is termed 25 
a “ transmitter,” in which there are finger keys or stops that are allotted 
to the respective characters employed. There is also in this instrument 
a “ pulsator” that makes and breaks an electric circuit passing through 
a range of relay magnets, and opens and closes these until tho pulsator is 
stopped by the depression of one of the finger keys. 80 

The second part of my Invention relates to tho arrangement of tho 
respeotivo electric circuits that connect this transmitter with tho relay 
magnets and tho circuits that are operated by those relay magnets, and 
pass through tho printing telegraph instruments, a number of these 
instruments being placed in each circuit, so that ono transmitting 35 
instrument will opernto in unison any numbor of printing telegraph 



instruments, to the extent of hundreds, and in case of defect in any one 
local circuit tho other circuits will not bo disarranged. 


Tho third part of this Invention relates to the printing telegraph 
instruments themselves, with tho modifications in construction adapted 
5 to various uses, and tho appliances that arc employed in or with such 
instruments for effecting tho various operations or for preventing diffi¬ 
culties that may arise under different circumstances. 

In tho Drawings, Eig. 1 is a plan of tho transmitter, and a diagram is 
also shown representing tho circuits to tho relay magnets and printing 
10 instruments, in which two wires arc employed, one wire and circuit to 
the type wheel magnets, tho other to the printing magnets; in Eig. 2 a 
diagram is shown of tho transmitter and circuits to printing telegraph 
instruments operated by ono wire and electric circuit; and Eig. 3 repre¬ 
sents tho transmitting instrument by a vortical section. 

15 The shaft a of the transmitting instrument is preferably revolved by 
magnetism. Eor this purpose two stationary magnets arc used, ono of 
which a 1 is seen in Fig. 3, and there are three armatures 2, 2, 2; and 
upon tho shaft a is a circuit breaker 3 of alternate conducting and non¬ 
conducting material tlint opens and closes the circuit to tbc magnets a' 
20 alternately, so as to attract tbc armatures successively and revolve the 
sliaft a. The battery 0* operates this motor, the wires being connected 
at 4 to tho bed h of tbc machine, and at 5 to tho insulated binder, and 
from that to the magnets a' and to the lover and roller 0 of tho 
respective pulsators, thonco through tho shaft a and bed b to 4. Upon 
25 tho shaft a are governor balls b' that riso by increased speed and bring 
tho flange 7 of tho sliding sleeve into contact with tho adjustable insu¬ 
lated arm 18, Eig. 3, and tho friction will cheek tho speed, but it is 
preferable to connect therewith a wire 95, so that the electricity will be 
“ short circuited,” passing through 4, b, a, 7,18, and 95 to 5 instead of 
30 going through tho electro-magnets a', thus lessoning the power and the 
speed and maintaining uniformity in tho revolution of the motor. 

If tho governor balls act to connect a circuit through the magnets a 1 , a 1 , 
tho slight electro-magnetism remaining in tho cores of the motor magnets 
will net to detain tho armature in revolving, and thereby lessen the 
35 speed; and if the pin is below tho flange 7, and tho circuit to the motor 
magnets passes that way, then tho power will be checked when the 






6 A.D. 18/2.—N° 1453.' seduction, 

Edison's Improvements in Printing 2'elegrapha. 

maximum speed is attained by opening the circuit to said motor 
magnets. 

By a suitablo connection such as tho gearing 8, 9,10, tho shaft c is 
revolved with the desired speed. It lias two arms c\ c', on opposito 
sides, ono above the other, and these act in connection with two semi- 5 
circular ranges of finger keys d, d l . Beneath the bed b theso finger keys 
have arms d' ! , (P, converging towards tho center of c, and when one of 
tho keys d x is depressed its arm d a stops tho arm c’, shaft c, and 
gears 8, 9,10. The gear 8 is driven by friction, hence the motor and 
shaft a continue to revolve, but connected with the gear 8 is a pulsalor e 10 
mado of alternate conducting and non-conducting surfaces, and theso 
open and close the circuits to the distant printing instruments or to tho 
relay magnets. 

By bearing in mind that the parts are mnde so that tho pulsator e 
transmits the necessary number of pulsations to mako a complete 15 
revolution of the type wheels (at tho distant instruments by a step-by- 
step movement), each complcto revolution of the shaft c, it will be 
understood that the shaft c and the typo wheels revolve in harmony, and 
that when the shaft c is stopped by one of the keys d, or d', the typo 
wheels of the distant instruments uro stopped, and the position of the 20 
characters on the type wheels must be in harmony with the arrangement 
of the keys d, d\ and when the key is liberated, the shaft c nnd pulsator e 
resume their revolution and the distant type wheels also resume tho 
synchronous movement. 

The printing telegraph machines illustrated at A, A, arc operated by 25 
two wires, those shown at B, B, Pig. 2, uro operated by ono wire; hcnco 
with two wire instruments two ranges of relay magnets e', e', and c\ c* 
will be required, while only the range e' of relay magnets will bo needed’ 
with ono wire instruments. 

When two ranges of relay magnets are used, there are two rollers or 80 
contact springs 12 and 13, on insulated spring lovers; one is connected 
to the binding screw 14, the other to tho binder 15, nnd the parts aro 
positioned so that tho pulsator e, as it revolves, opens and closes tho 
circuit from tho battery through the relay magnets c\ to make nnd 
break tho circuit at 16 from the batteries c 4 , through the type-wheel 85 
clcctro-magncts in the distant instruments A. 


Specification. 


A.D. 1872.—N° 1453. 7 

Edison’s Improvements in Printing Telegraphs. 

The relay magnets c* will not respond, although tho circuit is closed 
by tho roller 13, because tho springs of the armatures of tho electro¬ 
magnets c* aro under considerable tension, and tho pulsator contact 
points are small and send but a very short impulse, but when tho 
6 pulsator e is stopped by depressing one of tho keys, tho roller 12 rests 
upon a non-conducting surface breaking tho circuit through c 1 , and tho 
roller 13 resting on a conductor closes the circuit through the relavs e", 
causing them to close the circuits at 17 of tho batteries e', hence they 
act in the distant instruments A in tho electro-magnets that effect tho 
10 printing. The pulsator c when employed with the single rnngo of relay 
magnets e', as in Fig. 2, causes the pulsations to be repeated at 10 
from the batteries e* to the distant instrument, and wlion the printing 
is effected by a pause on a closed circuit tho pulsator e is stopped with 
tho roller 12 in contact with the metallic portion of the pulsator, but if 
15 the printing is effected by a pause upon an open circuit tho roller 12 is 
in contact with a non-conducting portion of the pulsator e. 

I linve shown tho battery e 4 in three sections connected with the 
respective relay magnets and with three circuits, in each of which 
circuits there may be any desired number of printing telegraph instru- 
20 ments, and tho circuits are completed through the ground connections. 

The circuits to the transmitting instrument and the relay magnets 
may bo disconnected by a switch at d that may bo turned around to 
throw both batteries out of action, and tho circuits from tho batteries e 4 
will also be broken at tho relay magnets. 

25 It is preferablo to employ slotted cores in tho relay magnets and to 
mako theso cores short, say not over two centimetres in length, and it is 
preferable to employ a detached layer of wire around the outside of each 
electro-magnet helix, which in practice will bo found to lessen tho sparks 
at and tho burning of the contact points without decreasing the power 
30 of tho electro-magnet. This extra layer or layers of wiro should be put 
upon tho outside of each magnet in tho printing instruments to lessen 
tho spark duo to the discharge of tho induced magnetism from the iron 
cores. 

The printing telegraph instruments and tho appliances connected 
36 with them form tho third part of this Invention. 

Bigs. 6, 6, & 7 aro vertical sections of the printing instruments; 
Bigs. 8 and 9 are elevations endwise of tho printing lever; and Big. 10 









* _A.D. 1872.—N° 1453. ^ 

Edison's Improvements in Printing Telegraphs. 
is a plan of tlio instrument. The baso/of tho instrument is of metal 
with frames/ 1 that support tho typo wheel shaft g, upon which is the 
typo wheel or wheels (l, l',) and tho electro-magnet h is employed to 
moyo a lover h\ and hy a stcp-hy-stcp movomont from pawls or wedge- 
actmg teeth i operating upon a toothed wheel k tho typo wheol will ho 5 
moved around progressively hy tho electrical pulsations aforesaid actin'- ' 
in tho magnet h. ° 

. Tll ° oIe otro-magnot m actuates tho printing lover m' to givo the 
impression, and this electro-magnet m is energized when tho typo wheol 
fbrp b rktin UrnCd ’ 011,1 ^ Pr ° 1)0r lettCr ° r obaractcr brought into position 10 

The arms 20 extend up sufficiently to carry a reel with tho strip of 
paper, and the types on the wheel are inked hy a roller 21. A spring 22 
Figs, o & 8, may ho used to press tho ink roller upon tho types. 

Wherever the before described parts arc shown in the various figures 15 
the same letters of reference are applied. 

The magnets m and h are adjustable vertically by screws 23, 24, that 
pass through the bed/and act upon tho cross bars cariying the magnets 
and the soft iron cores of the electro-magnets are hy preference made 

:m:f n r m f S,0t ; aSSCCnin ^ 4 ' SOthat the rcs ' ( iual magnetism 20 
^dl he fredy d."charged, and the helix are preferable when made of fine 
Mire without insulating covering wound hy machinery, and with a layer 
of paper between one layer of wire and the next. The line wires 
of the electric circuits arc connected with tho binding screws 20 for 
the magnet h, and with the hinders 27 for tho magnet m. 25 

*——«*•*■— m. 

„ U F ™‘l M 7', r ” ! ’° m ”” 01 ln» wfcol, wliilo 11,0 

other type wheel is not being printed from. 

Second. Means for bringing all tho typo wheels in tho various printing 30 
instruments into unison hy turning them around to a unison or Lnninf 
point and then liberating them all at once, so that all start together Md 
thus errors in printing are avoided. ° ’ d 

Third. Means for moving the strip of paper alon<- Tho i i 

* * K8 ' ”• “■»* *2.. ** sJiajt 35 


)3poc!Qcation. 



A.D. 1872.—N° 1453. * 

Edison's Improvements in Printing Tele graphs. 
shaft y; to this is connected a T lover o’, and upon tho printing lever 
»»' arc two stops or pins 30 & 31, positioned so that when tho 
typo wheels are stopped at one point and tho printing lover is moved, 
tho pin 30 taking one end of tho lover o’ will shift tho typo wheels in 
5 one direction, and if turned around another notch (of k), the other pin 
will act on o\ ns tho printing lover is moved, and shift the typo wheels 
the other way. Upon tho printing lever *»» is a shield o ! of thin metal 
under which tho strip of paper passes and in which shield is in an opening 
so that one type wheol will print through tho opening, tho other being 
10 kept from touching tho paper; thero is a printing pad p * on tho printing 
lover below tho paper at this point. ‘ ; 

Tho person at tho transmitting station brings cither type wheel into 
action hy stopping aU tho typo wheels at the proper position and 
allowing tho printing lover to ho moved hy closing tho circuit through 
15 tho printing magnot. As thero are hut two points where the chan°o 
can ho made either one way or tho other, a disk p is used on the typo 
wheel sleeve or shaft with a notch, and tho cam p > is on either one side 
or tho other of tho disk, so that tho parts cannot shake out of place. 

Tho typo wheels may he shifted endwiso hy a magnet q and lever q' 
20 see Fig 11 , acting on the sliding sleevo o. In this case the electric 
circuit passes through tho magnet h, then through the magnet q and tho 
toothed wheel k, on the typo wheel shaft, g is to ho of the character 
shown in Fig 7, so that tho rotation of g will ho half a space (of k) 
as tho lover h l is attracted hy h, and the other half spaco as tho lever IP 
2o is drawn hack hy its spring. If therefore tho circuit is kept closed 
through h and q, tho typo wheel l will bo held in position to ho printed 
from, hut if tho printing circuit through m is closed when tho electric 
circuit through h, q, is broken, then tho wheel l' will he in position for 
being printed from, tho spring / moving tho typo wheels to the left, Fi<- 
30 1. Tho types on l, P, in this instance must ho positioned so that tho 
type on one wheel is inline with tho space between two types on tho 
other wheel. 

If tho armature <f of the magnot q is permanently magnetized, then it 
will either ho attracted or repelled, according to tho polarity of tho 
3o electric current passing through q, therefore hy this modification one 
type wheel will ho brought to position for printing by a positive current 
and tho other hy a negative current. The same is the case with tho 








10 


Specification. 


A.D. 1872.—N° 1453. 

Edison's Improocm cnts in Printing Telegraphs. 

types on the wheels shown in Figs. 12, 14, but in theso Figures the 
shifting is accomplished mechanically instead of electrically by levers or 
inclines r, r\ moved by the printing lover >»*, and acting against the 
notched wheels r 1 r\ These parts are positioned so that with a closed 
electric circuit the lover or inclino r will press against the side of the 6 
wheel r 1 and shift tho type wheels to the left to print from tho wheel l' 
and tho lever or incline r' will not be operative bccauso it will pass into 
tho notch in r 5 , as shown in Figs 13 & 15, but when the printing lever 
m l is moved with tho electric circuit through h open, tho lever or inclino 
r x will operate on r 1 , and shilt the type wheels tho other way, and bring 10 
tho type wheel l into position for printing from. 

Where the characters on the type wheels arc positioned in two rows ns 
in Fig 10, with tho characters in one row opposito tho spaces in the 
other row, it is necessary that the type wheel should bo turned around 
upon its axis a distnneo equal to half a space to bring ono row of 15 
characters in position for being printed from, and the other row where 
there will not be any impression on account of the spaces between tho 
types coming over the impression pad. I accomplish this by a T headed 
spring bolt s that enters one of two notches on an arm 35, that extends 
from the sleeve of tho type wheel. When this bolt s is raised ns in Fig 2 0 
18 by the impression lever »»> tho type wheel and arm 35 can bo turned 
by a wedge tooth s‘ on the lever in 1 , acting against one of the inclined 
faces of tho arm 30. If the type wheel is to be moved tho other way 
half a space the type wheel is rotated further around so that tho wedge 
tooth s’ acts the other way on the opposite face of the inclino 30. ° 2 5 

When the printing lever recedes, as in Fig. 17, tho T head of the bolt 
8 holds tho typ 15 wheel in place by falling into tho appropriate notch 
in 35. A similar movement is given to tho type wheel by tho devico 
shown in Fig. 8, wherein tho lever o> shifts tho cam 30 and turns tho 
typo wheel partially around upon its axis; in this case the movement 30. 
may either be an entire letter space so as to print from alternate letters 
or characters, ono set of characters being in position for impression 
when shifted ono way, and tho intermediate letters or characters being 
in position for printing when shifted tho othor way. ~ 

Figs. 10 and 20 are plan views of the machines in which the two 35 
type wheels arc employed as before; but instead of moving tlic type 
wheels, the printing levers arc made in two parts, with separate im 


Specification. 


11 



A.D. 1872.—N° 1453. 

Edison's Improvements in Printi ng Telegraphs. 

pression pads, as seen in Fig. 21, and notched wheels i-, r\ arc attached 
upon tho shaft g instead of tho sleeves o, as in Figs. 12 & 1-1, and 
although both tho printing magnets in, in', are energized only ono 
printing lever in' can movo bccauso tho finger r' rises in the notch 
6 of tho wheel r\ see Figs 19, 21, and 22, and the other lever w>‘ i 3 
stopped from rising because its finger r comes in contact with tho 
projection or tooth of tho notched wheel i*, thus ono typo wheel l 
wiU bo printed from on tho open circuit (through h), and tho other 
wheel P will bo printed from when the circuit through A is closed. 

10 In Fig. 20 tho sopnrato impression pads and levers aro controlcd 
electrically instead of mechanically. In this case the arm -15 on tl.c 
axis of tho typo wheel lever closes the circuit, as seen in Fig. 23, to 
tho magnet in when tho magnet A is energized, and on the open 
circuit of tho magnet A, tho said arm 45 will close tho circuit through 
15 the mugnet in', and thereby an impression will be taken when tho type 
wheels stop rotating from either the wheel l or l', according to whether 
the wheels aro stopped on an open or a closed circuit through A. 

It is to bo understood that tho pulsations in A and the vibrations of 45 
arc too rapid to allow either magnet m or in' to be energized until a 
20 pause takes place and tho type wheels stop. 

In instruments where there is but one wire passing through both the 
printing magnet in and tho type wheel magnet A, as seen in the small 
inverted plan, 24, there will bo a movement of tho printing lever 
each pulsation that is sent for setting the type wheel if there is not a 
25 resistance to tho movement of tho printing lever that cheeks that move¬ 
ment during tho ordinary pulsations; but that resistance is overcomo 
uring a pause sufficient for developing tho full power of the printing 
magnet. This resistance to tho movement of tho printing lever may bo 
a spring, but tho weight m\ Figs. 7, 9, and 24, is preferable, as it 
30 prevents by its inertia a sudden movement, and when in motion tho 
inertia aids the power of tho clcctro-magnct in striking the pad against 
ic pnper with a sufficient blow to make a good impression. 

In Fig. 25 this resistance to tho movement of the printing lover is 
obtained by employing an air cylinder and piston, the latter boin- con- 
3o ncctcd to the lever «,> by a rod in". In this case-tl.e pulsations in tho 
magnet A operate to set tho typo wheel l or l' by a step-by-step move¬ 
ment; but they do not movo the impression lover in' sufficiently for 








12 


A.D. 1872.—N° 1453. SjwctRc&tion* 

Edison's Improvements in Printing Telegraphs. 
printing becauso tlic spring m" is noting upon (lie same, and tho air 
cushion in tho cylinder formed between tho piston and tho cylinder 
arrests any sudden movement, and tho spring »»“ acts between tho 
pulsations to keep (ho piston from gradually forcing tho niroutof tho 
cylinder j but when tho circuit is kept closed at tho transmitting station 5 
tho printing lever is allowed to move and givo tho impression, as the 
rod in' 1 moves tho piston and displaces the air cushion sufficiently to 
allow of this movement. The piston may have a valve to open as tho 
lever descends so as to allow tho printing pad (o move rapidly away 
from the typo wheel. 

The next feature of this Invention relates to an automatic dcvico for 
bringing all tlio type wheels to a unison or harmonious starting point. 
Ordinarily it is not necessary to rotate the type wheels more than two 
revolutions before the required letter will bo in position for printing. 
Tho unison is brought into action by giving to tho typo wheels two 15 
or more revolutions, and in tho act of so doing bringing into action 
a stop that arrests tho further movement of the typo wheel, but the 
pulsations aro continued sufficiently to bring up to that stop any 
typo wheels that may bo out of unison, and then upon operating the 
printing lever a movement is given to the unison stop that liberates 20 
the type wheels all at once, and they arc then in position for starting 
again in unison. The most convenient unison is an arm o' with tho 
end in a screw thread o= on the shaft g, and a pin 50 that stops 
against tho end of that arm, and when tho printing lover m' is moved 
the arm o is lifted out of tho screw o 5 by tho forked bar 53, and a 25 
spring 51, Figs. 9 & 10, returns it to a normal position. Tho pin 50 
may bo in the side of a disk, and a volute groove in tho disk take the 
place of a screw. 

' In Figs 5 & 8 an arm d> is shown on the typo wheel shaft g, taking 
in succession the teeth 54, on tho arm o', and drawing it down into the 30 
path of 60, tho stop o* is lifted by the bar 53, as before, when tho 
printing lover is moved. 

In instances whero tho typo wheel is moved half a space on closin- 
tho circuit and tho printing takes place on an open circuit, a unison 
wheel can bo employed, such as shown in Figs. 0 and 20. In this 35 
instanco tho magnet h draws down tho pallets i and holds tho ratchet 
wheel k and the separate ratchet wheel k' in tho position shown in FK 20 



Edison's Improvements in Printing Telegraphs. 

so that the point 00 on tho printing lover m' will not as a wedgo and 
force around tho typo wheel l, and tho wheels k' and k ono tooth at a 
time, as tho printing lever is moved by tho magnet m, but when tho 
space (made by removing ono tooth in tho wheel k\ Fig. 20) arrives 
5 at tho point 00 tho turning of tho typo wheel will ceaso becauso thero 
is nothing for tho point 00 to act against. 

Tho printing pad p‘ may be a small rubber or clastic roller, so as to 
turn and present ditTcrent sides to the impression. 

To movo tlic paper along a pawl u is employed and a roller or 
10 segment v. As tho impression lever is raised tho pawl u is forced upon 
tho paper, holds tho same, and feeds tho strip along tho required 
distance. 

Tho lover o', Figs. 7, 9, and 10 is moved by a pin on the printing 
lever in a slot in the lover o', and a holding pawl to, Figs. 9 and 10, acts 
15 to prevent the paper drawing back. 

In Fig. 6 tho pawl it has an arm that is connected by a link 68 
to tho printing lever in', so that as the lever rises tho paper is first 
caught by the pawl «, and then the parts movo together as the lever o' 
is swung by tho link G2 ; there is a slight looseness in the joint of tho 
20 link 02 that allows tho pawl u to bo pressed upon tho paper before tlio 
other parts move. Tho pawl may be made to slido and movo tho paper 
along in a shallow trough, and tho end of tho sliding pawl, coming 
against a stop as tho printing lever and pawl aro moved, gives the feed 
motion to tho paper. 

25 What I claim as my Invention and desire to sccuro by Letters Patent 
is,— 

First. Tho pulsator e driven by friction in combination with tho 
rango of finger keys and tho arms c', c 3 , substantially as and for tho 
purposes set forth. 

30 Second. Tho revolving pulsator c in combination with tho relay 
magnets and connections of tho local and main lino circuits, sub¬ 
stantially as sot forth for actuating tho printing tolegraph instruments 
in their respective circuits, substantially as set forth. 

Third. Tho governor b x and flange 7 in combination with tho circuit 
36 connections to tho magnets of tho motor, substantially as and for tho 
purposes set forth. 


A.D. 1872.—N° 1453. 







14 


Specification. 


A.D. 1872.—N° 1453. 

Edison's Improvements in Printing Teleg raphs. 

Fourth. Two typo wheels, Fig. 11, sliding endwise of the shaft, in 
combination with an electro-magnet to move such type wheels in ono 
direction, and a spring or its equivalent to return the typo wheels to 
their former position, substantially as set forth. 

Fifth. An clectro-magnet in tho same circuit ns the typo wheel 6 
magnet, and operating to give end motion to two typo wheels' when tho 
circuit is closed, in combination with a magnet in a separate circuit, to 
give the impression, substantially as set forth. 

Sixth. The notched wheels r=, r\ Figs. 12 & 14, in combination 
with the type wheels l, l', and mechanism substantially ns set forth, 10 
for moving the type wheels or tho printing pad or shield, to select the 
type whed from which the impression is to ho made, substantially as set 

Seventh. Two type wheels with the characters of ono in line with tho 
spaces between tho characters on tho other, and a step-by-step move- 15 
ment that is operative when tho electric circuit is both closed and 
opened, m combination with the notched wheels r=, ,* and mechanism 
forth° CCtlUS tb ° tyP ° " hCCl t0 b ° l )rinted from > substantially as set 

Eighth. The conical faced notched wheels r>, r', Figs. 14 and 15 in 20 
combination with the inclined stops r, r>, and typo wheels l, P, sub¬ 
stantially as set forth. 

Ninth The swinging levers r, >•', Pigs. 12 , 13 , actuated by the 
printing lever »\ in combination with tho type wheels l, P, and notched 
wheels r-, r\ substantially as set forth. 2Q 

Tenth. The combination of two type wheels and a printing lever 
with mechanism moved by the printing lever, substantially as sol 
forth, for printing from one type wheel when the type wheel circuit 

th ° ° tbCr WhCn tbat ChCUH » AsItaSy 

Eleventh A shifting movement derived from tho printing lever ^ 
operating m ono direction with a closed circuit, and in the aZ 
direction with an open circuit, substantially as set forth. 

Twelfth. Tho bolt s, arm and notches 35, and fork *30 in • ,• 

’f' a t„. wheel or wheel., ]»,l„ 8 r „ g0 . ^ 

Ihe love, „nd wedge tooth M „d for the pun,,... Sj, 


Specification. 


15 


A.D. 1872.—N° 1453. 

Edison's Improvements in Printing Telegraphs. 

Thirteenth. The cam 30 moved by the T lover o> and pins 30,31, upon 
the printing lever, in combination with tho typo wheel l and sleeve 0, 
substantially as and for tho purposes sot forth. 

Fourteenth. Tho wheels r 3 , r\ Figs. 19, 22, projections r, r\ and 
6 levers >»', ro M , in combination with tho typo wheels l, P, substantially as 
set forth. 

Fifteenth. Two separate printing lovers and their respcctivo magnets 
in the same or branch circuits, in combination with two typo wheels 
positioned ns specified, and mechanism substantially as sot forth, for 
10 proventing an impression from ono of tho typo wheels while tho other 
is bciug printed from, substantially ns set forth. 

Sixteenth. Tho circuit closing arm 45, Figs. 20, 23, and connections 
to tho respcctivo mngnots m, m', in combination with tho printing 
levers m\ m'\ typo wheels l, P, and actuating mechanism, substantially 
15 as set forth. 

Seventeenth. Tho printing lever and weight »»' in combination with 
the typo wheel and an electro-magnet, for tho purposos and as set forth. 

Eighteenth. Tho combination in one eleetric circuit of two or more 
type wheel magnets, and two or more printing magnets, and two or 
20 more weighted printing levers, substantially as set forth, whereby tho 
printing will bo effected by tho same pulsation used to bring tho typo 
wheel to place, hut only when the printing magnet has accumulated 
sufficient forco to givo a blow by tho weighted printed levers, sub¬ 
stantially as sot forth. 

2o Nineteenth. Tho air cushion, Fig. 25, applied to and combined with 
the printing lever and its magnet in a printing telegraph instrument, in 
tho manner and for tho purposes specified. 

Twentieth. Tho arm 0 ' and stop 50 upon tho shaft g in combination 
with the arm o\ teeth 54, and forked bar 53, moved by tho printing 
30 m> ’ th ° parts bein ° arranged and operating, substantially as set 

Twenty-first. Tho wheel k* and tooth CO, actuated by tho printing 
lover in combination with tho typo wheel l, wheel k, and pallets i, 
substantially as and for tho purposes sot forth. 

35 Twenty-second. Adjusting tho typo wheel to tho unison point by tho 
movement of the printing lover, wliilo tho typo wheel pallets are in tho 








Specification. 


16 A.D. 1872.—N° 1453. 

__ Edison'a Improvements in Print ing Telegraphs. 

opposite position to tlmt which they occupy when the typo wheel is 
being printed from, substantially as set forth. 

Twenty-third. The pawl « upon the arm o’, connected by the link OS 
■with tho lever m' in combination with the slotted link 02, that swings 
tho lever o' to feed the paper, substantially as specified. 6 

Twenty-fourth. Tho spring 22, attached to tho paper reel arms 20, 
and capable of being swung aside, in combination with tho inkin" 
roller 21, sustained by arms from tho cross bar a’, as set forth. 

Twenty-fifth. The electro-magnets, provided with slotted cores, and 
applied to a printing telegraph instrument, substantially as and for tho 10 
purposes set forth. 

In witness whereof, I, tho said Thomas Alva Edison, havo here¬ 
unto set my hand and seal, this 21st day of October, A.D. 1872. 

__ THOMAS A. EDISON, (l.s.) 

witnesses, ' 

Ciia*. n. Smith, 121, Nassau St., Now York, N.Y. 

Harold Serrell, 


LONDON: 

Printed by George Edward Eyre and William Sfottiswoodp 
Printers to the Queen’s most Excellent Majesty. 1872. 







































































































A.D. 1873, 27 th FsDRVAnr. N° 735. 


Circuits and Instruments for Chemical Telegraphs. 


LETTERS PATENT to Thomas Alva Edison, of Newark, in tho State 
of New Jersey, United States of Amorica, for tho Invention of 
“ Impbovemehts ih Cibcditb a he Ihbtbdhehts fob Chemicai Teieqbaphs.” 
Scaled tho 20th May 1873, and dated tho 27th February 1873. 


PROVISIONAL SPECIFICATION left by tho said Thomas Alva Edison 
at tho Office of tho Commissioners of Patents, with his Petition, on 
tho 27th February 1873. 

I, Thomas Alva Edison, of Newark, in tho State of Now Jersey, 
United States of America, do hereby dcclaro tbo naturo of tho said 
Invention for “Impbovemehts ih Cibcuiis ahd Ihbtbdmehtb poe Chemicai 
Teieobaphs,” to bo as follows:— 

On long telegraph lines tho pulsations that produco tho dots and dashes 
upon the chemical paper becomo so much attenuated os to bo indistinct 
or to run into each other. The rapidity of tho transmission is therefore 
lessened with tho increase in tho length of tho lino. - 

My improvements are to obtain greater rapidity in transmission 
in conscguenco of cutting off tho tailings of tho dots and dashes by 
neutralizing tho attenuation of tho pulsations. 












2 A.D. 1873,—N“ 735. B SSX 

Edison’s Impta, in Circuits and Instruments for Chemical Telegraphs, 

I have discovered that the counter current sot up in an clcctro-magnot 
or induction coil, when the circuit is broken, will noutralizo the attonua- 
tion of tlio pulsation. I therefore introduce suoh magnet in a shunt or 
branch circuit, so that in tho discharge of the magnetism the roverso 
current shall operate to clear tho line of tho tailings. G 

Tho electro-magnet or induction coil is sometimes introduced in a 
branch circuit from the lino to tho earth. At other limes it is in a shunt 
contiguous to tho receiving instrument. 


Two or moro stylus or pens, with shunt circuits and differing magnets 
to each, ensuro lcgiblo characters in one of tho several lines of 10 
characters. 


At local stations drop copies can bo taken by dividing tho circuit, 
placing tho magnet in the branch, or the samo thing can bo done in a 
branch circuit running to tho earth, or tho magnet may operate a 
sounder or call. A glass of water, with the ends of tho lino wire and 1G 
tho ends of local circuit wires to the receiving instrument, may bo 
employed for drop copies. When a resistance is placed in the main line 
nnd a circuit breaker is in tho lino operated with great rapidity so ns to 
keep tho lino charged statically, tho message will bo sent by the perforated 
paper and stylus acting in a shunt that is connected with the line at 20 
both sides of the resistance. 


Tho. secondary current set up in an induction coil is emploved for 
repeating a message. The primary circuit from the transmitting instru- 
meat acts in one coil, and that induces a secondary circuit in another 
coil connected with a receiving instrument. This device becomes an 05 
induction relay that acts with as great rapidity as the automatic ban* 
mitting instrument. 


The secondary circuit may act in a second induction relay, or it mav ' 
bo used for drop copies, or for branch circuits running off from tho main 
hne. In order to clear tho lino from surplus electricity batteries are an 
connected with tho line at suitable distances apart, with their poles 30 
opposed to the main battery, but of much less power, and these batteries 
servo to neutralize or aid in neutralizing tho tailings, and render tho 
mark upon the chemical paper clear and distinct. These reaction 

batteries are either in tho main lino or in branch or shuut circuits 3G 


Specification. A.D. 1873.—N° 735. 3 

Edison'a Impta. in Circuits and Instruments for Chemical Telegraphs. 

SPECIFICATION in pursuance of tho conditions of tho Letters Patent, 
filed by tho said Thomas Alva Edison in tho Great Seal Patent 
Olllco on tho 27th August 1878. 

TO ALL TO WHOM THESE PRESENTS SHALL COME, I, TnOMAS 
5 Alva Edison, of Newark, in tho State of New Jersey, United States of 
America, send greeting. 

WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 
Patent, bearing dato tho Twenty-seventh day of February, in tho year of 
our Lord Ono thousand eight hundred and seventy-three, in tho thirty- 
10 sixth year of Her reign, did, for Herself, Her heirs and successors, givo 
and grant unto me, the said Thomas Alva Edison, Her special licence 
ihnt I, tho said Thomas Alva Edison, my oxccutors, administrators, and 
assigns, or such others as I, the said Thomas Alva Edison my executors, 
administrators, nnd assigns, should at any time ngreo with, and no others, 
1G from lime to timo and at all times thereafter during the term therein 
expressed, should and lawfully might make, use, exercise, and vend, 
within tho United Kingdom of Great Britain and Ireland, tho Channel 
Islands, nnd Islo of Man, an Invention for “ Impbovemehts in Ciscdits 
ahd Insteomehts foe Chemical Telegbaphs,” upon tho condition (amongst 
20 others) that I, tho said Thomas Alva Edison, my executors or adminis¬ 
trators, by an instrument in writing under my, or their, or ono of their 
hands nnd seals, should particularly describe and ascertain tho nature of 
the said Invention, and in what manner the same was to bo performed, 
and eauso tho same to bo filed in the Great Seal Patent Office within 
25 six calendar months next and immediately after tho date of the said 
Letters Patent. 

NOW KNOW YE, that I, tho said Thomas Alva Edison, do hereby 
declare the nnturo of my said Invention, nnd in what manner tho samo is 
to be performed, to bo particularly described nnd ascertained in and by 
30 the following statement, reference being made to tho Drawings hereunto 
annexed, nnd to tho letters and figures marked thereon (that is to 
say):— 

Before this Invention telegraphic circuits had been arranged with a 
rheostat to regulate tho portion of tho electric pulsation passing to tho 
85 chemical paper, and allowing tho other portions of tho pulsation to pass 
along tho main lino or to go to the earth as a leakage. In these eases 











^ A.D. 1873.-N 0 735, Specification. 

Edison's Impls. in Cirenila and Instruments for Chemical Tel egraphs. 

the rheostat (lid not produce any countor curront, and served only to 
direct portions of tlm electrical waves through tho chemical paper, but 
the tailing and attenuation of tho mark was not avoided, and upon 
long lines theso marks usually ran togothcr, because there was not suffi- 
went time for tho electric action to coaso, or tho lino to freo itself beforo 
another pulsation succeeded, and tho lino becamo surcharged. 

In all cases it has been desired to obtain tho most perfect insulation 
of the hnc to avoid tho use of powerful batteries, and to lessen atmos- 
phono influences. It lias however been found that when tho insulation 
is impaired by atmosphoric influences tho marks upon tho chemical 
papor aro moro distinct, because tho surplus electricity finds vent in 
currents to tho earth, lessoning tho tailing. 

. y bcn ™ olectro-magnct is charged by a pulsation tho electric action 
m tho circuit of which tho liclix of tho magnet forms a part is aug¬ 
mented, but when tho main or lino current is broken the magnet L 
^charging itself of tho magnetism that has been induced sets up 
momentarily a counter current or one of opposite polarity. 1 

I avail myself of these various conditions, and arrange tho circuits in 
uch a manner that tho electro-magnets which aro energized by tho 
P^a ion that makes tho mark on tho chemical paper servo to bonify 

W when H a - n UP ° n - tbatpap01 '’ but tbQt tbc counter curr cnt, sol 
attrition of P tr ai7 T Uit iS br ° kGDj sha11 nou( ™lizo tho tailing or 
letrama^net^to77 ? ^ ^°flthe:magnetism tan'the 

17 f01 ' tb ° ^ ° f VCry fGcbl ° ■»* 

lendcimg tho marks upon tho chemical paper sharp and clear and I 

wh i C ZnlacTd P 7 UP ° n l0DS bnCS 0n0 ° r m ° ro cartb con nections, in 
wi P to 0 K ”T clcctr 0 - ma S“ ets * ™th or without rheostats 
tinr.f n ? P p rtl0n of cun ’ cnts Passing to tho earth, such conncc 
8 an J clc °tro-magnets serving to freo tho lino from surplus electricity 

t» freo tho too tram m, attaumtioa of the prinrny pntotions. 

a.™ 5 Sit*, *» !r ^ «* 


specification. A.D. 1873.-—N° 735. S 

Edison's Impls. in Circuits and Instruments for Chemical Teleg raphs. 

m.which a strip of perforated paper is drawn along between tho (bum 
and stylus or roller to open and close tho main lino cbouit, and produce 
tho pulsations of electricity that travel over tho lino in tho direction of 
tho arrows3, and mako a mark at tho distant recording instruments 
C upon a strip of chemical paper drawn along between the stylus and 
roller. Tho current is divided, part passing by tho wbes 2, 2 , in what is 
called a shunt, and in this is placed tho clectro-magnot c, or an induction 
eoib As each pulsation ceases in tho main lino a reverse current is set 
up in tho shunt in the direction of tho arrows 4 by tho discharge of tho 
10 magnetism of tho coro of tho clectro-magnot or induction coil. This 
cuts off any tailings in the pulsation of tho main line, and prevents 
attenuation in tho mark on tho papor. 

The electro-magnet or induction coil is sometimes introduced in a 
branch circuit from the lino to tho earth, as at e. At other times it is 
16 in a shunt contiguous to tho receiving instrument. 

Two or more styluses or pens with shunt circuits and differing magnets 
to each ensure legible characters in one of tho several lines of characters. 
These aro shown at/,/ 1 ,/ 3 , Pig. 2, and it will be understood that tho 
electrical conditions differing in tho circuits to the different styluses that 
20 one of tho lines of marks on tho chemical paper is almost sure to be clear 
and legible, because of the electrical condition being correct. 

At local stations drop copies can bo taken by dividing tho circuit, 
placing the magnet c in the branch, as at g, Fig. 1, or tho same thing 
can bo dono in a branch circuit running to tho earth, as at e, or tho 
25 maguct may operate a sounder or call or a local cbouit, as at h, Pig. 2, 
"‘hero tho magnet o is represented as a relay operating in the local ebeuit 
from a battery k to tbc receiving instrument b. A glass of water, with 
tho ends of the line wire and tho ends of local circuit wbes to tho 
receiving instrument, may bo employed for drop copies, as seen at l, 
30 Pig. 2 . 

When a resistance or rheostat It, Pig. 2, is placed in tho main lino, 
and a circuit breaker o is in tho lino operated with great rapidity by a 
revolving magnetic motor p, or otherwise, so ns to^kcep the lino statically 
charged, tho message will bo sent by the perforated paper, and tho 
35 stylus acting in a shunt that is connected with tho lino at both sides of 
I the resistance, tho battery B charging tho lino dbectly through tho 

























6 A.D. 1873.—N° 735. Specification. 

Edison's Impls. in Circuits and Instruments for Ohemical Telegraphs. 
perforations of the paper, and producing pulsations of greater intensity 
than the static charge. 

The secondary current set up in an induction coil is employed for 
repeating a message. The primary circuit from tho transmitting instru¬ 
ment acts in ono coil, and that induces a secondary circuit in another 5 
coil connected with a receiving instrument. This dovico becomes an 
induction relay that acts with as great rapidity as the automatic trans¬ 
mitting instrument. 

In Figs. 3, 4, 5, 6 , & 7 these induction relays arc represented. Tho 
transmitting instrument a, battery B, receiving instrument b, and indue- 10 
tion coil or electro-magnet c, to react and neutralize the tailings as tho 
main line circuit is broken, are tho sarao ns before described, but tho 
pulsations of electricity from tho sending station only' pass through an 
induction relay coil t, and that, by tho well known principles of induc¬ 
tion, sets up a current in tho surrounding helix, Fig. 3, or connected 15 
helix it, Fig. 4, and this secondary or induced current either operates tho 
receiving instrument, as scon in Figs. 5 and C, or else it operates in a 
second induction coil l\ Fig. 3, and that becomes a relay and sets up 
another current in the second induction coil and this operates in tho 
receiving instrument. 20 

Fig. 7 illustrates connections that may ho made under this modo of 
operatingNew York is represented as the sending station. At New 
Brunswick a drop copy is being taken by the secondary or induced 
current from the induction relay. At Philadelphia the induction relay 
coil n is connected to earth at v, and to tho lino wiro extending to Pitts- 25 
burgh, and there operates in the receiving instrument. At Ilnrrisburgk 
'the line passes through an induction relay that sets up a current in tho 
line reaching to a receiving instrument at Buffalo. At Baltimore a 
connection is sliow’n from the relay coil n to Cincinnati, and tho main 
pulsations from New York extend through to tho receiving instrument at 30 
Washington. 

In order to clear the line from surplus electricity reaction batteries aro 
connected with the lino at suitable distances apart, with their poles 
opposed to the main battery, but of much less powor, and theso batteries 
servo to neutralize or aid in neutralizing tho tailings, and render tho 35 
mark upon the chemical paper clear and distinct. These reaction 


I Edison's Impls. in Circuits and Instruments for Chemical Telegraphs. 

batteries aro either in tho main lino or in branch or shunt circuits. Theso 
reaction batteries aro marked to, and by roforoncc to Figs. 0 , 8 , 9 ,10,11, 
12, & 13, tho arrangements and operations will bo apparent. 

In Fig. 8 thero aro several branch circuits Jr, in which aro placed 
3 5 rheostats or resistances E that may bo adjustable, and also batteries to 

f that aro of tho proper power, and placed with the opposito polo to tho 

0 lino to that of tho battery B, so that the line is operated upon in detail 

j| at suitablo distances apart, say every ono hundred miles moro or less, 
|| and tho line freed from tailing, and tho sarno is opposed to tho main 
|| 10 current but not sufficiently powerful to neutralize tho same, or to inter- 
| fere with the transmission. Theso batteries to aro so proportioned or 

I adjusted as to bo equal to tho static current or electricity generated by 

I tho passago of the main current. 

I In Fig. 9 tho sumo parts aro employed, but tho opposition batteries to 

| 15 aro placed in tho main lino and distributed along the same. The branch 
I circuits to tho earth, with resistances E, act with the local opposition 
§ batteries to establish currents counter to tho main current. 

In Fig. 10 tho effect produced is tho same as before described, but in 
place of rheostats there aro condensers l 3 , and the opposition local 
20 batteries to acting upon tho condensers establish an opposite polarity on 
the plates of tho condensers that arc connected with tho lino to the polarity 
of such plates when influenced by tho transmitting battery, thereby 
neutralizing the tailings by charging tho lino statically in opposition to 
that from tho main current. 

25 Tho condensers may bo connected with tho opposition local batteries 
in tho manner seen in Fig. 11, so that the plates that aro connected to 
tho line will bo influenced by tho other plates of tho condenser that aro 
connected with the earth and tho other pole of tho battery, the operation 
being similar to that beforo set forth. 

30 In Fig. 12 tho parts arc tho same in their operation as those beforo 
described, but instead of ordinary batteries cups «, containing platina or 
carbon strips and aoidulntcd water, aro employed, so that when tho pul- 
! sation on tho main lino ceases to charge such cups a momentary rovorso 
current is established to neutralize tho tailings by instantly freeing tho 
I 85 lino of any electric charge. 
















Specification. 


3 A.D. 1873.—N° 735. 

Edison's Impls. in Circuits and Instruments for Chemical Telegraphs. 

In Fig. 13 tho lino battery to is introduced at the receiving station to 
neutralize any local currant that may leak from ono insulator to another 
(upon tho telegraph poles v that support tho lino wires), and tend to 
charge tho lino sufficiently to produce a light continuous mark upon the 
paper, tho battery to not being sufficient to interfere with tho pulsations 5 
for tho messago, although its poles aro opposed to tho samo. 

Tho electro-magnet or magnots c may bo used at tho transmitting end 
of the lino either with or without the magnets at tho receiving instru¬ 
ment. 

In Fig. 11 this arrangement is shown. Thoro is a rheostat or rcsis- 10 
tanco It in the shunt 2, 2, and tho electro-magnet or induotion coil c is 
connected at both sides of tho rheostat. Either polo of tho battery B 
may bo connected to tho lino. The effect of this is that when tho circuit 
is open part of the current passes upon tho lino and part returns to tho 
battery through the magnet c, tho rheostat boing adjusted to direct tho 16 
required quantity through the magnet. 

When the circuit is broken tho reactionary discliargo of tho magnet 
nets in tho opposito direction to the static discliargo of tho lino, and 
neutralizes it or restores the normal condition of tho line instantly, and 
thereby prevents tho tailings at the receiving instrument. 20 

What I claim as my Invention, and dcsiro to sccuro by Letters Patent, 
is,— 

First. An elcctro-magnot or induction coil applied with a chemical 
telegraph to neutralize tho tailings in tho main lino by tho discharge of 
induced magnetism. 26 

Second. Two or moro styluses to mark on a strip of chemical paper, 
and the combination therewith of shunt circuits and induction coils, or 
magnets of different sizes. 

Tim’d. A rapid pulsator o, to cliargo tho lino constantly through a 
rheostat It, combined with tho transmitting instrument, in a shunt of 80 
iho main lino connected at both sides of the rheostat. 

Fourth. A coil in which a secondary current is set up by a primary 
noil, in combination with connections from that secondary coil to the lino 
or a rceoiving instrument. 


SpocIficAllon. A.D. 1873.—N° 735. 9 

Edison's Impls . in Circuits and Instruments for Chemical Telegr aph. 

Fifth. Ono or moro batteries in tho main lino, or connected therewith, 
having thoir polos opposed to tho main lino curront to neutralize tailings’ 
in tho pulsations. ° 

In witness whereof, I, tho said Thomas Alva Edison, have hereunto 
6 set my hand and seal, this Twenty-fourth day of July, A.D. 1873. 

_.. THOMAS ALVA EDISON, (l.s.) 

Witnesses, v ' 

Cha". H. Smith, 

121, Nassau St. 

10 Now York. 

nAnom Serrele, 

121, Nassau St., 

Now York. 


LONDON: 

Printed by George Edwaiid Eyre and William Spottiswoodb, 
Priutors to tho Queen’s most Excellent Majesty. 1S73. 













































A.D. 1873, 25 th April. N° 1508. 


Electric Telegraphs. 


LETTERS PATENT to Thomas Alva Edison, of Newark, in tho Stato of 
Now Jersey, United States of America, for the Invention of “ Im- 
PBOVEMEHTS IH ElECTBIC TeIiEQBAPHB.” 

Sealed the 5th August 1878, and dated tho 25th April 1873. 


PROVISIONAL SPECIFICATION loft by tho said Thomas Alva Edison 
at tho Office of tho Commissioners of Patents, with his Petition, on 
the 25th April 1873. 

I I, Thomas Alva Edison, of Newark, in tho Stato of Now. Jersey, 
,United States of America, do hcroby declare tho naturo of tho said 
1 Invention for “ Impbovemehts in Electbio Teleobaphs," to bo as follows 


[ In cables and long telegraph lines thoro is a Emit to tho speed with 
I which perfect signals can bo transmitted and received, whethor tho 
receiving instrument consists of an electro-magnet, a galvanometer, a 
relay, or a chemical telograph instrument. This limit in speed arises 
from tho fact that tho moment the lino or cablo is charged by tho 
battery being connected a static charge is instantly sot up which is in an 











2_ A.D. 1873.—N° 1508. 

_ Edison's Im provements in Electric Telegraphs. 

opposite direction to tho dynnmio charge, and the tendency is to defor 
tho rccoption of the signal at tho distant station, and at tho moment of 
breaking tho battery connection tho static chargo disperses by dividing 
at tho centre of resistance and going in both directions, one part going 
to tho ground at tho transmitting station in a direction opposed to tho 5 
battery, and the other part going towards tho rccoiving instrument in 
tho samo direction as tho provious current from tho battery. This 
electrical condition is of sufficient duration to render tho signals unin¬ 
telligible at tho receiving instrument after a certain speed is attained. 
Tho time of discharge is directly proportioned to tho resistance at tho 10 
points of discharge at tho ends of the line, and tho result is that tho 
speed of the instruments is limited to tho speed with which the lino will 
free itself through tho channels aforesaid. 

My Invention relates to the discovery of a method of neutralizin'* tho 
effects of the static charge in any length of line or cable by balancing 15 
the electric forces, and the discovery of a point of no electric tension or 
zero as regards the static charge, so that tho receiving instrument when ' 
located at that point will bo operated by the rise of tension produced by 
a pulsation that is connected at such receiving instrument and made as 
instantly and definitely operative as tho pulsation given atthotrans- 20 
mitting station. I obtain this point of no tension by forming at tho 
receiving end an artificial line, having an equal resistance and electro¬ 
static capacity or capacity for producing static charges as that of 
the cable or land lme, and connect this with tho line or cable, and 
place between the cable and the artificial lme tho receiving instrument, 25 
1 Inch lienee is in tho centre of resistance and static accumulation • when 
t us balance is obtained tho signals are received perfect, and tho rapidity 
is governed only by tho strength of tho battery. The artificial line fa 
made with an adjustable rheostat; liquid in a tube is preferable 

I connect between tho rccoiving instrument and tho earth ono or more qo 
condensers or other accumulators of static clcetrieity, which are “So 
adjustable by having them in sections, and bringing one or more sections 

zislx a u ite v° - to »■>— «■. 

resistance coiMiV 1 mayaI *° bo do110 Pacing a very iiigU adjustable 


Specification. A.D. 1873.—N° 1508. 3 

_ Edison'8 Improvemen ts in Electric Telegraphs. 

Tho modo which I prefer is to keep my transmitting battery in circuit 
at all times, and inoludo in tho samo circuit another battery of equal 
power with opposito poles, so that when both-arc in thcro is no curront 
generated, and tho resistance of tho wiro to earth is no moro than tho 
5 resistance of tho battery. 

Tho transmission of a pulsation is mado whon tho circuit is closed 
through tho perforation in tho paper, or otherwise, so as to short circuit 
or shunt tho neutralizing battery and send a current upon tho line. 

Tho curront at receiving paper is shunted through a resistance so as to 
10 preservo a constant and equal resistance which tho chemical rccoiving 
paper docs not give, owing to being moro damp in ono place than 
another. In balancing tho resistance and static current tho resistance 
of tho instrument fa to bo added to tho lino, nnd tho resistance of tho 
two equalized by tho same amount of resistance in the artificial cablo or 
15 -line. 

If tho receiving instrument is out of the centre of resistance towards 
the line tho pulsations will be weakened by the static chargo acting 
against the pulsation; but if tho instrument is towards tho artificial 
cable on tho other side of tho zero point tho signals or characters will bo 
20 slightly prolonged owing to tho static chargo discharging in tho samo 
direction as tho current. It is at this point that I prefer to place tho 
instrument, because by placing an electro-magnet in tho shunt of tho 
receiving instrument I obtain enough counter discharge from that magnet 
to cut off this prolongation locally, and this discharge from tho magnet 
25 will not interfere w-ith tho lino that has only a local effect on tho 
receiving instrument to prevent tailing on tho chemical paper. 


SPECIFICATION in pursuance of tho conditions of tho .Letters Patent 
filed by tho said Thomas Alva Edison in tho Great Seal Patent Office 
on tho 25tli October 1873. 

30 TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS 
Alva Edison, of Newark, in the State of New Jersey, United States of 
America, send greeting. 

WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 
Patent, bearing date tho Twenty-fifth day of April, in tho year of our 
















4 


Spocificatio 


A.D. 1873.—N° 1508. 

Edison' s Improvements in Electric Telegraphs. 

Lord One thousand eight hundred and sovonty-tbreo, in tho thirty- 
sixth year of Her roign, did, for Hcrsolf, Hor heirs and successors, givo 
and grant unto me, the said Thomas Alva Edison, Hor special liconco that 
I, tho said Thomas Alva Edison, my executors, administrators, and 
assigns, or such others as I, tho said Thomas Alva Edison, my executors, 6 
administrators, and assigns, should at any time agree with, and no others, 
from timo to time and at all times thereafter during tho term therein 
expressed, should and lawfully might make, uso, oxo'roiso, and vend, 
within tho United Kingdom of Great Britain and Ireland, the Channel 
Islands, and Isle of Man, an Invention for “ Impbovemehtb is Eiectbic 10 
Teleobaphs,” upon tho condition (amongst others) that I, tho said Thomas 
Alva Edison, my oxeoutors or administrators, by an instrument in 
writing under my, or their, or ono of their hands and seals, should 
particularly describo and ascertain the nature of the said Invention, and 
in wliat manner tho same was to he performed, and causo tho same to 16 
ho filed in tho Great Seal Patent Office within six calendar months 
next and immediately after tho date of tho said Letters Patont. 

NOW KNOW YE, that I, tho said Thomas Alva Edison, do hereby 
dcclaro the nature of my said Invention, and in what manner tho same 
is to ho performed, to he particularly described and ascertained in and 20 
by the following statement, reforenco being mado to tho Drawing here¬ 
unto annexed, and to the letters and figures marked thereon (that is to 
say):— 

This Invention is for increasing tho speed of transmission and 
neutralizing tho effect of static electricity at tho receiving instrument. 26 
An artificial lino is employed at tho opposite side of tho receiving 
instrument to tho cable or main lino, hence between suoli instrument 
and the earth connection. This artificial lino is mado with a rheostat or 
resistance, and with a condenser or other accumulator of electricity, and 
tho artificial lino is so adjusted as to resistance and static ebargo as to 30 
equal tho lino or cablo; tho consequence is that tho receiving instrument 
is placed at a neutral point or zero as regards olectrio tension and static 
charge, from which tho static charges will dischargo or equalize itself 
both ways, and tho messago will bo received with great rapidity and 
reliability, according to tho pulsations from tho transmitting station. 36 

In the Drawing Eiguro 1 illustrates my Invention in tho form that I 
find most generally avaUablo. Tho batteries a and 0 nro connectod in 


Specification. A.D. 1873. - N° 1508. 3 

_ Edison'8 Improvements in Eleclrio Telegraphs. 

opposite positions, tho positive poles being towards cnoli othor, and tho 
negativo poles connected to tho ground g and lino l respectively. Tho 
transmitting instrument o is in a circuit d to tho battery b, in which 
circuit d is a resistance e. When tho circuit d is brokon, tho two 
6 batteries a, b, neutralize each othor, and thoro is no charge sent on tho 
line, but when tho circuit d is dosed through a perforation in tho paper 
or by a finger koy or otherwise, tho bnttory b is short circuited, and 
the battery a being unbalanced sends a pulsation on tho line. Tho 
artificial lino between tho receiving instrument / and tho earth g x is 
10 made by introducing a rosistanco or rheostat at r, preferably a tube con¬ 
taining liquid with adjustablo points. This rheostat is made to balance, 
or equal or nearly equal the resistance of tho lino l, and tho instrument/ 
and the condenser s or other accumulator of static electricity is of a 
capacity to about equal that of tho lino, honco the receiving instrument 
15 will occupy a zero or neutral point in regard to tho statio charge from 
which tho static charges will dischargo botli ways to g and g'. Tho 
condcnsor or accumulator s should bo in sections to bring in a greater or 
less number of sections by switches. 

When tho receiving instrument is chemical, the paper is preferably 
20 prepared by dipping it in a solution of at least ono pound of iodide of 
potassium in ono gallon of water, to wliioh has been [added a snmll 
quantity of flour. This pnpor cannot bo maintained at uniform moisturo,. 
honco its rosistanco to tho passago of elcctrioity varies; this is com¬ 
pensated for by tho shunt circuit t, in which is a resistance « sufficient 
26 to direct tho necessary amount of electricity to tho paper to make the 
mark and allow tho remainder to pass to tho artificial lino, thus tho 
varying condition of tho paper does not change the rosistanco of the 
lino. 

When an clcctro-magnet is energized and tho circuit broken, a 
30 pulsation is set up in tho opposito direction to that passing into such 
magnet; I avail of this to provont tailings upon tho chemical paper by 
so applying tho cloctro-magnot that its dischargo will aid in restoring 
tho lino or instrument to a normal condition instantly, and at v I havo 
shown an cleotro-magnot for this purposo. It will bo scon that this 
36 olcctro-magnot will discharge itself within a short local circuit containing 
tho receiving instrument, and that tho reactionary current thorofrom 
moving in tho opposite dircotion to tho main current frees tho receiving 
instrument from any tailings caused by tho disohargo of statio electricity, 












6 A.D. 1873.—N° 1508. Specification. 

Edison's Improvements in El ectric Telegraphs. _ 

and this magnet v may bo omployed in many places to effect the object 
boforo named oven whon tlicro is not an artificial lino. 

In some instances with very long linos there may ho intermediate 
artificial lines arranged as aforesaid, or reactionary magnets with.branch 
circuits to the earth to cither rccoivo drop copies in such branch circuits 5 
or to freo tho lino of static electricity, and aid in obtaining tho signals 
perfectly at tho last receiving station with tho greatest rapidity. 

Pigs. 2 and 3 represent tho samo parts as heforo described, but in 
Pig. 2 only a single battery is shown, and tho resistance e is between 
the lino and tho earth to regulate tho proportion of electricity sent over 10 
tho lino by adjusting such rheostat to prevent too great return to tho 
battery through such rheostat. 

Prom tho foregoing it will be understood that what is to bo attained 
is tho instant restoration of tho lino at tho receiving instrument. to a 
normal electric condition after it has been disturbed by tho passage of a 15 
pulsation of electricity, so that the speed will not be lessened by falso or 
reactionary currents, and that the chemical paper will only be marked 
with a dot or dash when the transmitting instrument is operative. In 
some lines this condition is promoted by tho devices shown in Figs. 3 
and 4, and theso are preferably used in addition to tho balanced circuit 20 
at tho receiving end, as shown in Pig. 3, or may bo used separately 
therefrom as represented in Fig. 4. Tho transmitting instrumont c, 
circuit d, from the battery «, and tho rheostat c are as before mentioned, 
and tho battery may bo arranged with either its positivo or negativo to 
the lino, and there is a condonscr 7i, Pig. 3, or ono or more induction 25 
coils or electro-magnets /*, Pig. 4, connected in tho shunt d at both 
sides of the rheostat e. Tho effect of this is that when tho circuit is 
opened through tho perforation of tho transmitting paper tho current 
passes upon tho line and also through tho magnet or condenser h hack to 
the other polo of tho battery, tho rheostat e diverting tho required 30 
quantity. As tho circuit d is broken by tho intervening papor, tho 
reactionary discharge or condition of opposite polarity takes placo from 
tho magnet or condenser, and acting in tho opposite direction oithor 
neutralizes the static discharge of tho lino or becomes a path for its 
return to tho earth connection of tho battery, so that tailings or pro- 85 
longations of tho marks on tho chemical paper at tho receiving instru¬ 
mont are effeotually prevented. In long lines an clcctro-magnot or 


A.D. 1873.—N° 1508. 7 

_ Edison's Improvements in Eleetrio Telegrap hs. 

resistance r may bo introduced in a branch circuit /* to tho earth to 
react upon tho lino to effect tho samo object, and a small battery may bo 
introduced in said branch with its poles opposed to tho main current 
that would pass over that branch, and thereby aid tho reactionary effect 
5 of tho magnot in clearing tho lino, and lesson the tailings upon tho 
chemical paper. 

Claims. 

I claim as my Invention,— 

First. The artificial line on the opposite sido of tho receiving instru- 
10 menttotho lino or cablo for positioning tho recoiving instrument at a 
I neutral point for tho purposes set forth. 

Second. An electro-magnet or condenser positioned in relation to tho 
receiving or tho transmitting instrument, substantially as set forth, so 
that the reactionary discharge from said magnet shall aid in restorin'* 

[ 0 0 nornia l* condition of the lino cablo or receiving instrument. 

In witness whereof, I, the said Thomas Alva Edison, havo hereunto 
set my hand and seal, this Sixteenth day of September, A.D. 
1873. 


| 9A TIIOMAS ALVA EDISON. 

|20 Witnesses, 

Cua". H. Smith, 121 Nassau St., N.Y. 

Geo. T. Pinckney, „ „ „ 


(L.S.) 


„. . ,, „ LONDON: 

n DWAIt . D EYM and WlUttH SPOTTISWOODE, 
Printers to tho Queen’s most Excellent Majesty. 1873. 































A.D. 1873, ll//< September. N° 2988. 


Perforated Telegraphic Paper. 


LETTERS PATENT to Thomas Alva Edison, of Newark, in the State 
of New Jorsoy, United States of America, for tlio Invention of 
“ Impbovemehts ih Pebpobated Papeb pob Teieobapbic Pubfoses, and 
ih Meahs pob Receivibo ahd Tbahsmitiihq with the same.” 

Sealed the 3rd Maroh 1874, and dated tho 11th September 1873. 


PROVISIONAL SPECIFICATION left by tho said Thomas Alva Edison 
at tho Oflico of tho Commissioners of Patents, with his Petition, 
on tho 11th September 1873. 

I, Thomas Alva Edison, of Newark, in tho Stato of Now Jersey, 
B United States of America, do hereby dcclnro tho nature of tho said 
Invention for " Impbovemehts ih Pebpobated Papeb pob Teleqbafhic Pob- 
poses, ahd ih Meahs pob Receiviho ahd Tbahsmittiho with the same,” to bo 
as follows:— 


Tho paper instead of being perforated in telegraphic characters is 
10 perforated in groups that represent Homan or block letters, or other 
characters, and tho messago is rccoivcd upon chemical paper in dots 
that cither touch each other or arc sufficiently close to clearly represent 








A.D. 1873.—N° 2988. 


Edison's Improvements in Perforated Telegraphic Paper. 


by their aggregation the lotters or characters transmitted, thus making 
the automatic telegraph strip as convenient as the printed message, and 
obtaining the rapidity of the former, and avoiding the risks of tho 


The paper is perforated, one letter or character at a time, by an 5 
instrument operated by finger keys substantially similar to thnt shewn 
in English Patent, No. 1751, A.D. 1872, except that the punches arc 
massed together, preferably in a square, and the connections between 
each key and the punches are such as to select and operate such of tho 
punches as will perforate the paper to represent tho letter or character 10 
upon the finger key. It is preferable to employ twenty-five punches in 
a square of five each way. 


The transmission from the perforated strip may bo by as many lines 
of telegraph wires as there are rows (five) of perforations, so that there 
may bo a transmitting stylus to each row of perforations, and also a pen 1r 
' ° l ': ra '° t0 011 the chemical paper, and these pens arc to bo 
sufficiently* close together to produce the letter transmitted in consc 
quenee of the contiguity of the marks. The message can he mado 
through one lmo wire by having the transmitting paper at one end and 
the receiving paper at the other, and travelling at proper speed - and a on 

roller for V* ^ 7°” a at ri & Lt an S? les <*> tho shall of tho 
lol oifo! the paper, so that these spring fingers draw across the per 

samelnsSh i mak °, C ° ntaCt thr ° UBh thc Potions, and at the 
hy the spring, p“ wi 

Lg compaSely ^ ° f *** arc 

same speed «7so y ’ rCSPeCtlV0 ^ movia S at tho 


“ T r sa n id PU Thoma C s° lla '°™ mms of tl10 L «ttcrs Patent, £ 
• Office on tho 4th March 1874. ' 1S<m m tll ° Gl ’ cat Seal 1>atcnt 

C0ME>TnoMAs 

America, send greeting. ^ f N °' V Jcrsc y> Ulli tod States of 


Specification. A.D. 1873.—N° 2988. 3 

Edison's Improvements in Perforated Telegraphic Paper. 

WHEREAS Her most Excellent Majesty Queen Victoria, by Her 
Letters Patent, hearing date thc Eleventh day of September, in the year 
of our Lord One thousand eight hundred and soventy-throe, in tho 
thirty-seventh year of Her reign, did, for Herself, Her heirs and 
5 successors, give and grant unto me, tho said Thomas Alva Edison, Her 
special licence that I, the said Thornns Alva Edison, my executors, 
administrators, anil assigns, or such olliors ns I, thc said Thomas Alva 
Edison, my executors, administrators, and assigns, should at any tiino 
■ agree with, and no others, from time to time and at all times thereafter 
10 during the term therein expressed, should and lawfully might make, 
use, exercise, and vend, within the United Kingdom of Great Dritain 
and Ireland, thc Channel Islands, and Isle of Man, an Invention for 
“ Ihpbovehents in Pebfobated Papee fob Teeeoeaphic Purposes, and in 
Means fob Receiving and Tbansmitting with tiie same,” upon tho 
15 condition (amongst others) that I, the said Thomas Alva Edison, my 
executors or administrators, by an instrument in writing under my, or 
their, or one of their hands and seals, should particularly describe and 
ascertain the nature of the said Invention, and in what manner tho 
same was to be performed, and cause the same to be tiled in the Great 
20 Seal Patent Office within six calendar months next and immediately 
after thc date of the said Letters Patent. 

HOW KNOW YE, that I, thc said Thomas Alva Edison, do hereby 
declare thc nature of my said Invention, and in what manner .the 
same is to be performed, to ho particularly described and ascertained in 
25 and by the following statement, reference being made to thc Drawing 
hereto annexed, and to the letters and figures marked thereon (that is 
to say) 

In the Morse system of telegraphy thc operator frequently receives 
the message by sound, and writes thc same out as received. 

30 In thc printing telegraph system thc printed slip is usually delivered 
as received. 

In tho ordinary automatic system thc paper has to be punched or 
composed, and at tho receiving station tho message on tho chemical 
_ P a Por has to bo translated and written out by hand, or printed by a key 
33 printing instrument. 

Each system has its defects or disadvantages. Thc Morso system is 
slow, and requires a large number of wires. Thc printing telegraphs 









A.D. 1873.—N° 2988. 


Edison'8 Improvements in Perforated Telegraphic Paper. 


are expensive, liable to inaccuracies and injury, and limited in speed to 
the fingering of tlio keys. The automutio system is rapid on tho line, 
but tlio composing of the mossngo and tlio writing of it out at the 
receiving station are comparatively slow operations. 

The object I havo in view is to print tlio message chemically, thereby 5 
tho message, as received upon a strip of papor, is ready to ho folded and 
sent to its destination, and the rapidity is equal to any automatic 
transmission. 


I accomplish this object by perforating tho strip of paper used for 
transmitting with groups of holes, representing by each group a letter 10 
or character, the perforations being arranged to produce as nearly as 
possible the block or Homan letters or characters. 


Tho transmission of tho message by the lino wires may be in the 
usual manner by a roller or stylus, and a lino wire to each row of per- 
> forations, so that if there arc five rows of perforations there will bo five IB 
stylus points or rollers, each connected to a line wire, and at the 
receiving instrument there will be five pens or stylus points near 
togetha and tho letter received will be in dots corresponding to the 
position of the perforations in the transmitting paper, and by their 
aggiegationm gi-oupsthc letters will be clearly delineated, and formed 20 

l)Inercanb P e C d , "T'f! cLai ' actcre > so “ «,c strip of chemical 

^Wehvered^ndthe re-writing or printing of the message 


The message as received being the counterpart of that transmitted the 

L' t'i raord ° f 2 


wS,tu 1 , "*? S “ ^ 3 

M herein described, with tramnritr 1 “ u8mithll S l'apcr, perforated 

i-meperote^eX 05 " d 


•nd adapted to * P1 °°° ° r I»*»tioi». ! 


Specification. A.D. 1873.—N° 2988. s 

Edison’s Improvements in Perforated Telegraphic Paper. 

Kg. 2 shows tho chemical paper with tho same word printed there¬ 
upon by the dots running together, or being sufficiently closo to each 
other, to show tho respective letters. , 

Fig. 3 is a plan of a portion of tho perforating machine. 

5 Fig. 4 is an elevation endwiso of tho punches, and Fig. 5 is a partial 
section longitudinally. 

I find that five lines of perforations are tho most convenient for pro¬ 
ducing perforations in imitation of block letters or characters, and have 
shown and described such, but I am not limited in that respect. 

10 Itcforonco is hereby made to Letters Patent, No. 1751, granted in 
Great Britain, June 10th, A.D. 1872, for a machine for perforating 
paper for tolegmpliic purposes, which, with tho modifications herein set 
forth, is adapted to punching tho characters in the strip of transmitting 
paper. 

15 Instead of having two lines of punches i, i, as in aforesaid Patent, 
these punches i, i, are twenty-five in number positioned in a square of 
five each way, and as closo together as convenient. Each punch is 
connected with its slide plate k, and these slide plates k aro side by side, 
and supported in tho frame of the machine, so that they can be moved 
20 endwise with facility, and actuate the punches to which they aro con¬ 
nected respectively. The punches slide in the plato in, and n is the die 
plate, as in said Patent. 

Thero might ho a spring to each slide plato k and punch i, hut I havo 
shown a levor k 1 passing through mortices in the plates k, and provided 
2B with a spring to draw all the punches and slide plates back to their 
normal position after they have been actuated. If the punches arc 
separato from tho slide plates each row r may bo provided with a lover l 
and spring o to return [or draw hack tho pimehes, and said levers l act 
within notches in tho punchos, mi shown. 

30 Tho shouldors or projections 8 arc provided upon tho slide plates con¬ 
tiguous to tho respective pressers e, and these projections 8 aro only 
upon such of the slide plates that requiro to he moved by tho pressor to 
which tlioy aro adjacent to oporato tho punches required to perforate the 
letter corresponding to tho ono on the finger key a, that is, connected to 
35 the particular pressor e, as in aforesaid Patent; and I remark that tho 
slide bars c and connecting cams f or forks to move the pressers e by 





6 A.D. 1873.-N° 2988. Specification. 

Edison's Improvements i n Perforated Telegraphic Paper. 
the fingor toys « may be similar to those shown in said Patent; and the 
lever u\ feeding clamp t, pawl it, rack bar v, and pawl 10 aro similar to 
tlio parts shown, and operate in tho manner described in the aforesaid 
Patent, and tkoroforo do not requiro further description. 

Prom tho illustration given in Pig. 1 tho general character of tho 6 
groups of perforations will be apparent, and in tho square of iwcnty-iivo 
i P unc hes tho proper ones can easily be selected to perforate any given 
letter or character sufficiently liko block letters to bo reliably read at 
the receiving station on tho chemical paper. 


T , . -w 

l claim as my Invention,— 

Hat A strip of paper containing groups of perforations representing 
ette rs or characters for use in transmitting telegraphic messages to bo 
received upon chemical paper in imitation of printed characters. 

papl^^n^^^ iS VT\^ king 8l ' 0UI,S ° f P"™ * a strip of 15 

^j=zaL- 

"P 011 «» „ 

myband and scalthis 

Witnesses, THOMAS ALVA EDISON. ( L .s.) 

GrT E p"' N ““ st ' H ™^ 


Trailed hy Geoiicp EDH-Aim°v TD0N! 






















A.D. 1875, 2nd February. N° 384. 1 


Multiplex Telegraphs. 


' ? ES PATENT to Thomas Alva Edison, of Newark, in the State of 
1Sc "' Jors °y» U,,,tctl States of America, Tor the Invention of “In- 
movements in Domex and Multiplex Teleobaphs.” 

Soalod the 25th March 1875, and dated the 2nd February 1875. ‘i 


PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison 
a 110 of the Commissioners of Patents, with his Petition, 
on tho 2nd February 1875. 

I, Thomas Awa Edison, of Newark, in tho State of Now .Tcrsoy, 
m od Slates of America, do hereby declare tho nature of the said 
nvonlion for ** In movements in Domex and Multiplex Teleobaphs,” to bo 
as follows 

Tho 0,) j cots of this Invention arc,- 

ls • Lo ^able two operators, one at each terminal station, to transmit 

stati , OUSly . OV01 ' ° nC Wirc ’ and lwo others> ono nfc cnch °f such 
ions, o receive such messages, and in- this respect my Invention is 
improvement in duplex telegraphs. 

























2 A.D. 1875.—N° 384. 

Edison's Improveme nts in Multiplex Telegraphs, _ 

2nd. To enablo four oporators, two at each terminal station, to 
transmit signals, and four other oporators, two at each terminal station, 
to rccoivo tho mossages, without cither interfering ncoossnrily with tlio 
other, and to uso only ono lino wiro'in so doing. This portion of my 
Invention is designated a quadruples or multiples tolcgrnph. 6 

3rd. To allow either oporator to signal tho distant station so that tho 
message may ho repeated to rectify any inaccuracies or omissions. 

4th. To repeat a messago received over ono wire hy either the duplos 
or quadruples telegraph into another circuit to send tho same to another 
or distant station. 

I remark that tho duplcs and quadruples tclographs can ho used 
hy the number of persons named, or they can ho used singly hy ono 
oporator at each end; and furthermore, that hy hearing in mind tho 
general principles of operation herein set forth the details of tho arrange¬ 
ments of tho batteries and mctallio circuit connections will ho apparent 
to an electrician. 

One of tho persons sending a messago employs a key that is con¬ 
structed so that it does not break tho circuit, hut that it connects more 
n- less of tho battery to tho lino; thus ono oporator works a distant 
instrument hy a riso and fall of tho electrical tension or energy, Tho 20 
other operator has a key that is made to reverse tho circuit connections 
without breaking tho continuity of circuit, and thus his message is 
indicated hy a change in tho polarity of tho current sent regardless of 
the tension or energy of tho battery power. These keys of the sending 
station are either operated directly hy hand or preferably hy an electro- 25 
magnet, a local circuit and a finger key for each, aud both ends of tho 
line are similarly provided with two transmitting keys, batteries, and 
ciromt connections, and also with the receiving instruments next 
spee e j hut I remark that tho receiving instruments aro also capable 
ot use in duplex telegraphy under systems of transmission heretofore 30 

‘ riS ° and faU ° f tcnsi0U l? 1,oduco th ° respective 

indications at tho two rccoiving instruments. 

The instrumentalities at each end for receiving tho messages consist, 

It of a receiving magnet; 2nd, of a polarised receiving magnet; 3rd, 

6th' of local f 0i ° f adjUBtablc rhcostats « resistances; and 35 
6th, of local cn-euits containing batteries and electro-magnels foming 


A.D. 1875.—N° 384. .5, 

_ Edison's Improvements in Multiplex Telegraphs. ~ 

tho instruments for rccoiving tho message by sound by a " Morse 
receiver,’’ or in nny other convenient manner. 

The instruments that arc required for either tho quadruplet or tho 
duplex systom of receiving nro selected and arranged with rofcroncc to 
5 the transmitting devices employed. With tho duplex system operated 
by rise and fall of tension, as aforesaid, tho polarized relay will not bo 
required, but tho receiving magnet is to he placed at a point that is 
neutral to tho message sent from that station but where it will bo 
influenced by the message received. To this end tho artificial lino 
10 composed of a rheostat preferably with a coudonscr in a shunt around 
the rchcostat is arranged so that its dischargomny compensate (he static 
discharge from tho lino, and this artificial lino is at ono sido of tho 
receiving instrument or instruments, and tho lino connection at tho 
other; aud the pulsations sent from the home station will he balanced 
15 in tho receiving instrument at that station, hut such receiving instru- : 
meut will respond to the pulsations from tho distant station beeauso tho 
distant pulsations arc unbalanced. 

The receiving magnet is sometimes made with two helices on one 
core, and ono helix is in tho artificial lino and the other in tho main 
0 me, and they are so wound as to opposo each other, aud lienee tho caro 
is no magnetized by tho outgoing current, but it is by tho current from 
10 istant station operating in the one helix. The polarized receiving 
magnet employed in the quadruplox telegraph is similarly arranged and 
J° Sltlonod50 ns 1° bo uniufluciiccd by tho current sent, but to respond 
m change of polarity in the current received; and when made with 
°ur eliccs around the two cores tho instrument becomes a differential 
Polarized relay or magnet. 

UuT^tT l ' 10 ? ondcnsol ‘ is usud 111 a sliullt around the rchcostat, either in 
30 it^clT * ^ *' n ° 01 ^etweea the receiving instrument and main lino, 
ai go and discharge as tho circuit is opened or closed neutralizes or 
placc° n r tCS <be c ^ cc ^ s * nt ‘ c ehargo and discharge that takes 
cc a M>nt same time, beeauso tho condenser is arranged so ns to 
sciiargo in opposition to tho static discharge. 

05 pjj Z*} 0 rcoeivin g instruments aforesaid when arranged for tho quadru- 
v C . c G ra l>h it is preferable to arrnngo the local circuit that is worked 


““balanced foroo 


receiving- instrument so that the sounder is operated by tho 


of a second local battery when the first local circuit is 










4 A.D. 1875.-N° 384. Specification. 

Edison'8 Imp rovements in Multiplex Telegraphs . _ 

broken by tho armature of such receiving instrument, thereby the 
sounder will be moro distinct in its response to the pulsation on tho 


r The main battery of tho lino is subdivided into two portions of 
unequal power for tho object heroin-beforo named, and one portion is 5 
always upon the line and tlio other portion is applied or removed by tho 
koy of one of the operators to incrcaso or lessen tho electrical energy. 
With this battery it is preferable that a resistance bo inserted in a branch 
passing around tlio battery to the koy, arranged to present the samri 
resistance to currents from tho distant station that that portion of tho 10 
battery itself presents when it is connected into the circuit so as to 
maintain equality of resistance. Either an induction coil or else cups 
of acidulated water with similar poles may be used in place of the con¬ 
denser before named when the devices are positioned, so that tho 
disehai'go from the coil or the cups on tho opening of the circuit opposes, 13 
compensates for tho effect of, or neutralisms the static discharge of the 
* line. 

Where two helices arc used upon one core and the line and artificial 
lines pass through those helices as aforesaid there may be a third helix 
on tho same coro between tho said two helices, and this third helix will ?0 
operate the receiving instrument by the induced current in the said 
third helix. 

A compound differential and polarized magnet may bo mado use of in 
tho quadruplex telegraph. In this instrument there arc two armatures, 
ono to respond to eliango of polarity and tho other to clmngo of electrical 25 
tension or energy from tho distant sending station, as aforesaid. 

When tho duplex or quadruplex receiving instrument is arranged to 

i -Tv 0 ?? SC " d tllC 1UCSSasc 01110anoUl “ station the polarized 
magnet is delicately adjusted so that tho magnetized tongue is energized 

nolSd t t0 ° lmUS ° S ^ tllG polarity of tl,c corca > this 30 

thl s7m! nUd ° l0SCS tho circuit for tllc rdny and operates 

°- thr ° U ? h aU clcotr °- ma S»ct and armature with 
. ., • 8 ? l levorsm S springs to act in tho relay circuit. Thcso 

ei emt connections are arranged so that on long lines the duplex 


■&5SS8t A.D. 1875.—N° 384. B 

_ Edison's Improvements in Multiplex Telegraphs. 

operate automatically at an intermediate station as a relay to and from 
a distant station oh long lines, tho principles of operation as aforesaid 
being borno in mind, tho receiving instruments being made to operate 
tho relay instruments and oirouits instead of acting upon a sounder. At 
5 tho intermediate or relay station switches will generally bo used to 
facilitate tho adjustment of tho lino and to throw in or out tho relay 
connections so as to work from or to cither end, or to allow tho end 
stations to communicato with caoh other by tho relay on long lines. 


SPECIFICATION in pursuance of tlio conditions of tho Letters Patent, 
10 filed by tho said Thomas Alva Edison in tho Great Seal Patent 
Offico on tho 31st July 1875. 

TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Thomas 
Alva Edison, of Newark, in the State of New Jersey, United States of 
America, send greeting. 

15 WHEREAS Ilcr most Excellent Majesty Queen Victoria, by Her 
Letters Patent, bearing date the Second day of February, in tho year of 
our Lord One thousand eight hundred and seventy-five, in tho thirty- 
eighth year of Ilcr reign, did, for Herself, Her heirs and successors, 
give and grant unto me, the said Thomas Alva Edison, Her special lieenco 
20 that I, tho said Thomas Alva Edison, my executors, administrators, 
and assigns, or such others ns I, the said Thomas Alva Edison, my 
executors, administrators, and assigns, should at any timo agreo with, 

• and no others, from time to time and at all times thereafter during 
the term therein expressed, should and lawfully might make, use, 
25 exercise, and vend, within tho United Kingdom of Great Britain and 
Ireland, the Channel Islands, and Isle of Man, an Invention for “In- 
PBovEMENTa ih Duplex ahd Mdltiplex Telegbaehs,” upon the condition 
(amongst others) that I, tho said Thomas Alva Edison, my executors - 
Qv administrators, by an instrument in writing under my, or their, or 
3 ,° one of their bauds and seals, should particularly dcscribo and ascertain 
tho nature of tho said Invention, and in what maimer tlio samo was 
to bo performed, and enuso tho same to bo filed in tho Great Seal 
; Talent Office within six calondar months next and immediately after 
the date of tho said Letters Patent. 















A.D. 1875.—N° 384. 


Edison's Improvements in Multiplex Telegraphs. 

NOW KNOW YE, that I, the said Thomas Alva Edison, do hereby 
declare tho nature of my said Invention, and in what mnnnor the samo 
is to he performed, to ho particularly described and ascertained in and by 
the following statement, rofcrcnco being mado to tho Drawings hereto 
annexed, and to tho letters and figures marked thereon (that is to say)6 
The objects of this Invention arc,— 

Eirst. To enable two operators, ono at each terminal station, to 
transmit simultaneously over one wire, and two others, ono at each of 
such stations, to receive such messages, and in this respect my Invention 
is an improvement in duplex telegraphs. 10 

■ Second. To enable four operators, two at each terminal station, to 

transmit signals, and four other operators, two at each terminal station, 
to receive the messages without cither interfering necessarily with tho 
other, and to use only ono line wire in so doiug. This portion of my 
Invention is designated a quadruplex or multiplex telegraph. 15 

■ Third. To allow either operator to signal'the distant station so that 
ptlie message may be repeated to rectify any inaccuracies or omissions. 

, Pourth. To repeat a message received over one wire by either tho 
uplcx or quadruplex telegraph into another circuit, to send the samo to 
another or distant station. 1 2Q 

I remark that the duplck and quadruplex telegraphs can boused by 

the number of persons named, or they can bo used singly bv one 

to an electrician. 110Ulfc comiectl ons will bo apparent 25 

Cmpl ° yS a « con- 

more or less of the battery to tlio ^ S ° thftt ik conncot3 

distant instrument by a rise and fall of ^ .° n ? OI,(3rator W01 ' ks » 

the other operator has a key that is m i ? ° Coh ' 10al tcnsi(m ov energy; 30 
tions without breaking ^ th ° oircuifc "mnoo- 

indicated by a changin '^ is 

tho tension or energy of the battorv y f t ° Urront sont . regardless of 
station, are either o/crated dLou/bvTn 1 ° SC ^ ° f ihe sondiu S 


Spcdficaiion. . A.D. 1875.—N° 384. *r 

Edison’s Improvements in Multiplex Telegraphs. 
lino are similarly provided with two transmitting keys, batteries, and 
circuit connections, and also with receiving instruments next specified, 
but I remark that tho receiving instruments aro also capablo of uso in 
duplox telegraphing under systems of transmission heretofore employed, 

5 wherein tho riso and fall of tonsion produco tho respective indications at 
tlio two receiving instruments. 

Tho instrumentalities at each end for receiving tho messages consist, 
first, of a receiving magnet; second, of a’polarized receiving magnet; 
third, of an artificial line; fourth, of adjustable rlioostats or resistances; 

10 and fifth, of local circuits containing batteries and electro-magnots 
forming the instruments for receiving the message by sound by a 
“ Morse receiver,” or in any other convenient manner. 

The instruments that aro required for either the quadruplex or the 
duplex system of receiving aro selected and arranged with roforonco to j 
15 tho transmitting devices employed. With the duplex system operated * 
by rise and fall of tension as aforesaid, tho polarized relay will not ho 
required, hut the receiving magnet is to he placed at a point that is 
neutral to the messago sent from that station, hut where it will be influ¬ 
enced by the message received. To this end the artificial line composod 
20 of a rheostat, preferably with a condenser in a shunt around the rheostat, 
is arranged so that its disclmrgo may compensate tho 'static disohargo 
from the line, and this artificial line is at ono sido of tho rcooiving 
instrument or instruments, and tho lino connections at tho other, and 
tho pulsations sent from tho home station will bo balanced in tho 
26 receiving instrument at that station, but such receiving instrument will 
respond to tho pulsations from tho distant station bccauso tho distant 
pulsations aro unbalanced. 

Tho receiving magnet is sometimes mado with two helices on ono core, 
and one helix is in tho artificial line, and tho other in tho main line, and 
80 they arc so wound as to opposo each other, and henco tho core is not 
magnetized by tho outgoing current, hut it is by tho current from tho 
distant station operating in tho ono helix. Tho polarized receiving 
magnet employed in tho quadruplex telegraph is similarly arranged and 
positioned so as ho uninfluenced by tho current sent, hut to respond to 
36 tho change of polarity in tho current received, and when mado with 
four helices around tho two cores, the instrument becomes a differential 
polarized relay or magnet. 









8 . A.D. 1875.—N" 384. specification 

_ Edison's Improvemen ts in Multiplex Telegraphs. 

When the condenser is used iu n shunt around tho rheostat, cither in 
tho artificial lino or between tho receiving instrument and main lino, its 
charge and discharge, as tho circuit is opened or closed, neutralizes or 
compensates for the offcot of tho static oliargo and disolmrgo that takes 
place at that same timo hccauso tho condenser is arranged so ns to 5 
dischargo in opposition to tho static discharge. 

In tho receiving instruments aforesaid, when arranged for the quadra- 
plox telegraph, it is preferable to arrange tho local circuit that is worked 
by such receiving instrument so that the sounder is operated by tho 
unbalanced force of a second local battery when tho first local circuit is 10 
broken by the armature of such receiving instrument, thereby tho 
sounder wiU be more distinct in its response to the pulsations on the 
lino. 

To ba f. C1 ' y ° f tb ? linc is su,,divi dcd into two portions of unequal 

LeTne°Md C tl JCC t h0r ° m ; beforo namcd > an(1 ° n ° Portion is always upon 15 
the line, and lie other portion is applied or removed by tho key of one of 

named, when tho devices ^ • ™ e<1 m pIaC ° ° f tbo con(le nser beforo 

the effect of, or neutralizes tlio°statio discbargoTuSinr 110118 ” 109 ^ 

line pass tlOTugu'thL^hdicos^'Tforosni th ° ^ ai ' tificial 

on tho same core between the snirl * . r * 1010 may 1)0 n tIu ‘ l ' d helix 
operate the receiving instrument "° lcllc , cs * and tllis third helix will 
third helix. S StlUmCnt by tb ° induced current in the said 3 0 

in tho quaruplox telegraph “in may bo mad ° use of 

one to respond to change of polarity Z th "° m '° two "futures, 


Specification. A.D. 1875.—N° 384. 9 

Edison's Improvements in Multiplex Telegraphs. 

magnet is delicately adjusted, so that tho magnetized tongue is energized 
to respond to delicate changes in tho polarity of tho cores, and this 
polarized tongue opens and closes tho oircuit for tho relay, and operates 
tho samo cither directly or through on clolcetro-magnct and armature, 
6 with circuit, closing or reversing springs to act in tho relay circuit. 
These circuit connections arc arranged so that on long lines tho duplex 
telegraph may repeat tho messages into another duplex telegraph to 
another distant station; or tho quadruplex telegraph may be mado to 
operato automatically at an intermediate station as a relay to and from a 
10 distant station on long lines, the principles of operation as aforesaid 
being borne in mind, the receiving instruments being mado to operato 
tho relay instruments and circuits instead of acting upon a sounder. At 
the intermediate or relay station switches will generally bo used to 
facilitate the adjustment of tho linc, and to throw iu or out the relay 
15 connections so as to work from or to cither end, or to allow the end 
stations to communicate with each other by the relay oil long lines. 

The essential instrumentalities aro,— 

First. Tho linc wire, marked on tho Drawing L. 

Second. Tho battery, marked D. 

20 Third. A circuit preserving key IC that serves to connect and dis¬ 
connect portions of tlio battery with tho line, and increase or dccrcaso 
tho electrical energy, or as otherwiso called, produce a rise and fall of 
tho electrical tension. This key K is made with an insulated spring 
upon it that comes into contact with tho metal of tho key when in 
25 normal condition, and so maintains a metallic circuit through tho key 
from the respective wires, but when tho key is depressed the spring 2 
comes against an adjusting screw 3 , to which another circuit wiro front 
other other portions of tho battery is connected, hence, the circuit through 
tho koy is never broken, but the new circuit through tho screw 3 is 
30 closed; thereby tlicro is no timo when tho circuit through this key is 
entirely interrupted, and tho wires to tho battery aro arranged so that 
more or loss of tho battery is applied to tho lino by this movement of tho 
key. 

fourth. A eircuit preserving and polo changing koy, called a reversing 
35 k °y. aui} marked It, K. This is constructed with a spring 4 acting (liko 
the spring 2 ) against tho screw 5 , and there is a second insulated arm 0 , 
either at right angles to the koy, as shown in tho Drawing, for greater 


I 

1 











A.D. 1875.—N° 384. 


Edison's Improvements in Multiplex Tclegruplis. 


clearness, or in lino with tho main portion of tho koy, and thoro is a 
second insulated spring 7 to this arm 6, and a circuit closing scrow 8. 
Tho construction of this is such that when in a position of rest ono pole 
of tho battery, say tho positive, is connected to tho lino, and tho 
negative to tho earth; but when tho koy R, K, is moved tho negative of fi 
tho battery is connected to tho lino, and tho positive to tho earth, and 
this is dono as aforesaid without the circuit being entirely broken at any 
point. 


Fifth. An electro-magnet that operates by a riso of olcotrical tension, 
but is not influenced by reversing tho polarity of tho current nor by tho 10 
weaker current that is constantly on tho line; this is marked M. Tho 
spring of its armature is adjusted so as to respond with tho rise of 
electrical tension, but not to respond to tho weak constant current in the 
lino. 


v 

W h ' 


Sixth. An electro-magnet with a magnotized or polarized tongue /, 15' 
and known ns a dillbrcnfial or polarized magnet, and marked D, M. 
tflns magnet is not operated by a rise and fall of the electrical energy, 
stron°" ly ^ a Cha ” S0 ° f P ° hrity ‘ '- 1,ctl101 ' tllG curront is "’enk or 


Seventh. Rheostats that servo to determine tho quantity of electricity 
flowing through one circuit, and to divert the remainder through 
refo !L° lrC ‘ ai ' C “ nrkC<1 R> and nUmbcred A* convenience of 


20 


The ground or earth connections or plates are marked G. 

th ” “1 •taolu » will ta h„™fta 

..o ..d tS “JItalpa. ud the two operator at 

•“» ««*» t,io o,zii rs ci. “ “ 

the polarity ’of the curront whether tw T ° °P orator royotsca 
the magnet D, M, responds It £ f ^ or weak ’ and 


/Specification. A.D. 1875,—N° 384. 11 

Edison's Improvements in Multiplex Telegraphs. 

tho distant stations, hence two, four, six, or eight persons can operate 
over ono wire, half of them being engaged in sending and tho other half 
in receiving. 

Having thus defined tho general principles of operation, the details 
5 will bo easily understood by reference to tho Figures of tho Drawing 
successively. 

Tho keys K and R, K, Figuro 1, may he operated directly by hand, 
but I prefer that tho operator use the finger koys a and h, batteries o 1 , J 1 
local circuit wires and olcctro-magnots c and d, with armatures to movo 
10 these keys K and R, K, respectively. Tho main battery B has a 
wire 10 from the key K that dividcstho battery into a larger portion 11 
and a smaller portion 12. When tho koy K is at rest the battery 12 is 
connected to tho lino L through tho connections 5, 0, 7,13, 14, and R 1 , 
and to tho earth through tho connections 10, K, 2, wire 10, 8, R, K, 4, 
15 and 17. "When tho key IC is depressed tho entire battery 11 and 12 is 
placed on tho line by connecting from 3 to earth G through 2,10, 8, 
R, K, 4, and 17. Now if the koy R, K, is operated either at tho samo’ 
time as K or separately tho polarity is reversed, whether tho electrical 1 
tension is high or low. Supposo tho current aforesaid was positive to 
20 lino and negative to earth, then if R, K, is depressed 4 will bo separated 
from R, K, and 7 from 0, and tho positive curront will go from 5 to 
earth G through 4 and 17, while the negativo will bo connected to tho 
lino L from 3 or K by spring 2, wire 10 by 8, 7,13, and 14, and R 1 to 
line L. 

25 It is to be understood that tho instruments at tho distant station arc 
the counterparts of those shown in Fig. 1; and having now described 
how tho pulsations of different polarity and of riso and fall of electrical 
tension aro sent it will bo apparent that they will at tho distant station 
operato tho magnet M or the polarized magnet D, M, tho currents 
30 passing from tho lino L by 20, M, 21, D, M, R 3 , 23, R 5 ,15,13, to earth 
through R, K, and its connections; a portion however passes by I!' 
and 14, and also a portion by R‘ to earth, according to tho relativo 
resistances of the various routes. 

It is now necessary to dcscribo why tho pulsations sent do not operato 
G tho receiving instruments at tho homo or sending end of tho lino. 

The instruments M nnd D, M, are at a neutral point to the pulsations 
sent, becauso tho electric current divides half going by 14, the other. 












A.D. 1875.—N° 384. 


j Edison's Im provements in Multiplex Telegraphs ■ - 

half by 1C, tho rheostats R* nncl R‘ being adjusted to offer tho samo 
resistance as tho rheostat R 1 and tho lino and distant instruments, honco 
hotweon 20 and 23 what is known as a, “ bridgo ” is formed and tho 
oleotric forces of tho outgoing current opposing each other equally the 
instruments M and I), M, aro not affected. Tho rheostat It* sorves to 5 
divert a portion of the current passing between 20 and 23 into tho con. ' 
denser O', and upon tho principles known to electricians the condenser 
reacts or sets up a roverso current when tho current is lessened or 
augmented, thereby tho effect in the instrument of tho static cliargo and 
discliargo duo to tho passago of the distant signalling current over such 10 
line aro neutralized by tho counter-discharges from tho condonsor. 

A secondary battery S, B, Kg. 10, composed of two or moro cups 
containing acidulated water and poles of tho samo materials may bo 
used in the “ bridgo ” to effect tho same object of neutralizing static 
discharge from tho line of the of the incoming current by an opposing or 15 
counter current set up when tho electrical condition is changed. The 
► condenser C 2 arranged around tho extremities of tho rheostat It* which 
forms the artificial lino is for tho purpose of generating an inductivo 
current to balance that due to the static induction of tho lino. Tho 
rheostat It 5 is for the purpose of regulating (by increasing and decreasing 20 
the resistance) the length and strength of the inductive current from C* 
to enable perfect compensation to be obtained on various wires and 
especially upon long circuits. 

The functions performed by tho condenser C 2 will bo equally as well 
performed by inserting an eleotro-magnct O' in tho circuit 1C, as shown 25 
m Kg. 10. The rheostat R«, Kg. 1, is adjusted to afford tho samo 
resistance as the battery B, hence when the operators at ono station aro 
balancing the outgoing currents upon tho receiving apparatus M and 
D, M, at that station by the adjustment of It* and It* the switch 13 at 
the distant station which is in connection with tho lino is to bo turned to 80 
the light so as to disconnect tho battery B from tho lino and allow tho 

s°Sn C °T f -VT thl ' 0USl1 tllUS th0 ^terynt tho distant 
currant. interfci '^vith the proper balancing of tho outgoing 

The receiving instruments M and D, M, may bo observed Lv tho aa 
receiving operators and the message read either by sound or inlnv otlm 
known way, but usually it will be best to use these as the 1“ ,7 

so Sr s x* £ 


Specification. A.D. 1875.—N° 384. 13 

Edison's Improvements in Multi plex Telegraphs. _ 

operates by its armnturo lovor, tho local oircuit from tho battery f in 
which is placed tho clcclro-mngnot g, and this in turn operates a second 
local circuit from tho battery in which is tho receiving instrument y\ 
which will usually be a sounder; tho circuit of / will oloso when M 
5 ceases to attract its armature, and tho circuit of /’ will closo when g is 
demagnetized, licnco the receiving instruments g l and M will pulsato 
exactly in harmony, and as the armature of g is not so delicately 
adjusted as the armature of If there will not bo any false pulsation 
reach g' as sometimes occurs in M, when the polarity of the current is 
10 reversed. 

The samo offects will be produced by the circuits shown in Figs. 2, 3, 
and 4. • In Fig. 2 the battery / will bo short circuited through tho 
armature of the magnot M when tho current docs not act in M, and 
hence tho battery f will not act in g, but when tho armature of M is 
15 attracted the circuit is broken and tho battery f has no other route, but- 
is obliged to act iu g, hence tho armatures of g and M respond simul-' 
tancously. * 

If the batteries / and /• be both connected to tho receiving magnot 
g, as shown in Fig. 3, and in reverse, so that they balance each other 
20 when the circuits of tho two batteries aro closed the clcctro-magnct g 
will not ho euergized, but this clcctro-magnct g will respond to tho 
battery f x simultaneously with the magnet M, because when tho arma¬ 
ture of 11 is attracted tho circuit of tho battery f is opened, and said 
battery f ceases to neutralize the effect of the battery f l . Tho samo 
25 effect will bo produced by connecting tho battery f to the wire between 
the helices of the magnet g, as seen in Fig. 4, and winding those helices 
so that tho battery current dividing and acting in both helices will 
produco similar polarity of tho cores, henco the magnetism will be 
neutralized, wliilo both circuits from the battery / are closed, but when 
30 ono circuit is broken by tho movement of the armature of M tho battery 
current acts in only ono helix and attracts the armature at tho samo timo 
ns tho armature of II moves. Tho polarized tonguo i of tho clcotro- 
magnet D, M, is shown iu Fig. 1 as acting as a rolny to the local oircuit 
containing the battery h and receiving magnet or sounder lc, and iu 
36 Fig, 5 this clcctro-magnct k acts a rolny to tho second local circuit 
nnd battery l, in which is placed tho receiving magnet or sounder n. 

In Kg. 0 tho differential polarized magnet D, M, instead of being 
in the same bridgo 20, 23, with tho receiving magnet M as before is 








u 


A.D. 1875.—N° 384. 


Edison's Improvements in Multiplex Telegraphs. 


mado as a compound differential polarized magnet, in which there aro 
four helices so wound that the outgoing current from U will operuto in 
tho helices 61, 02, while that from 15 will act in the helices 03, 6d>; and 
thoso holiccs being wound in opposite directions the cores passing 
through 01, 03, and 02, Oil, respectively, will not bo magnetized, tho 6 
magnetizing actions being opposed to each other, lienee the polarized 
tongue i between tho cores will not be moved one way or tho othor, but 
tho incoming current from the distant station will pass from L through' 
02, 61, to 1-1, thence through the bridge wire containing M, and also 
through R 1 and It 2 to earth through tho transmitting keys; owing to 10 
the great resistance of 11‘ (which should be equal to tho line) a verv 
small portion of the distant currents passes to earth by this route. Tho 
distant current in passing through the helices 02 & 01 rives the 

rS'thoT a POlm ' ity !° ath ' aCt thc t0nSUC * -y « tho other 

and 15 and tl n °'i ’ f 1U loduccd ncar tIlc dividing points of tho wires 11 
wound^a^posito^heeUon^so^that'tl^ 0 C0I f^° UIld ’ ^ lav ‘ n o k' vo helices 20 
each other in their temlnnnJ t ^ * ’? 0llt 3 0ln S currents neutralize 
through both helices • then J ° maSU . ctlZ0 tllc soffc iron core, passing 

going^urrent, but°tho current o^m?n^fi^ni' S tl U °V P t' 0 ^ UC0 ^ ^ c ou ^" 
in one direction through ii i ,• 0IU 410 distant station, passing 
through 3JS ^ 2 ° and baok * ether direction 25 

T“, ms f m ia tbo coro ' so ** ** 

current sent by tho key K 'ritT “jV” 11 ° f clcctl ' ical tc asion of tho 
aad tb ° polarized 

reversal of thc circuit r , les P oud6 > as aforesaid, to thc 
•htto. tt. koy E, K. at tuo distant 30 


11,0 Purpose, and r,raV«aM to if illt “ l “ c “ 1 

same instruments dm,, „ d d..“Sd In 

»«.W srfth Us „ m letters of Mtotl “ “ ll 


in »Uioi tl, 0 coils or'telta 'or'oVnt' 1 ' T?!'‘ " * I " m ‘ in K S- 9 - 


u -a 


•Specification. A.D. 1875.-N° 384. 15 

_ Edison's Improvements in Multiplex Telegraph s. 

movo tho magnetized tonguo i by tho change of polarity; but there is 
an armature M added, tho spring of which is adjusted so that tho 
armature responds to riso and fall of electrical tension, thus dispensing 
with tho magnet M and making tho ono compound magnet, shown in 
6 this Pig. 0, respond to tho change of polarity or olectrical tension, or 
both, at tho distant station; but this compound magnet is-uninfluenced 
by thc currents sent out at that station bccauso they aro balanced in 
their actions therein, as boforo described. Electro-magnets o, o', placed 
in branch or shunt circuits around the receiving magnet, set up counter 
10 secondary currents to neutralize tho secondary or induction discharge of 
tho electro-magnet D, M. 

In Pig. 8 a modification of tho circuit wires is shown. Tho magnet M 
and differential magnet D, M, are the same as in Pig. 7, but there aro 
_ l "’° artificial lines with rheostats .IP, IP', and condensers C\ and these 
15 are separately connected to tho respective magnets and to earth, so thatl 
tho outgoing currents can bo balanced in their action in D, M, by ono 
artificial lino to G and balanced in tho electro-magnet M by tho other 
artificial lino to G l independent of each other. 

In Pig. 10 connections are shown that correspond to thoso shown in 
20 Pigs. 1 and 5, so far as thc receiving portion of tho apparatus; thc 
transmitting koys K and It, K, are somewhat differently arranged. Tho 
battery is compound, part being opposed to thc other part. Thc 
hey It, K, in a position of rest is open, and the key K is closed, hence 
o ^ lc portions 30 and 32 of tho battery aro short circuited through K and 
-5 do not go upon tho line, and the batteries 31 and 33 still act in tho line, 
hut 31 overpowers and more than neutralizes 33, so that tho pro- 
pondcratiug force from 31 on the lino is negative, tho earth being 
connected to positivo; now’, if the key 11, K, be closed thc portions 30 
and 31 of tho battery arc short circuited, allowing tho portion 33 to act 
and reverse thc polarity of tho current, as the positivo pole of 33 is to 
io line. If tho key K is depressed tho short circuits of 30 and 32 aro 
broken, and these portions 30 and 32 of tho battery net in tho line, but 
contains a largo oxccss in the number of cells and acts with 31 to 
3 - “ outra lizo 82 and 33 and produco a riso of electrical tension on the lino; 
lenco by this arrangement tho rise and fall of tension and tho reversal 
° r 11,0 'polarity of thc currents aro attained without tho peculiar keys 
own in ligs. 1 and 7. D, M, Pig. 11, is a polarized relay haying tho 















16 A.D. 1875.—-N 0 384. Specification* 

_ Miaou’s Imp rovements in Multiplex Telegraphs. 

lino wire L attached to tho oross wire connecting the two spools togothor. 
l’lfo other ends aro connected, ono to n resistance coil lt“ and tho other 
to an ordinary clcetro-magnet o. Tho rosistnneo of o is equal to It 4 . 
Now when tho curront is made to circulate permanently through 
tho two coils of tho polarized relay D, M, and through o and It 4 , 5 
its effect is balanced in tho polarized relay M, as it passes in 
opposito directions through its two coils, but the magnet o is 
charged. Now, if the current be interrupted or suddenly decreased in 
strength tho iron cores of o set up au induced curront in the helices 
surrounding it, and this current circulating within tho circuit formed 10 
of 0, It 4 , and tho coils of the polarized relay D, M, passes in tho proper 
direction through D, M, to niako its cores magnetic, and tho todguo is 
thrown to one side. If now the circuit bo closed or the strength of tho 
current increased the magnet o will in tho act of charging set up another 
i 1 ct on jurrent, which now circulates in tho opposite direction, and 15 
brows tlio tongue of the polarized relay in the opposito directLu. Tho 

r dSj f°- n USt< f 50 ! hat thC WOak currcut 1Vom battery 12 at tho 
distant station will not produce sufficient induced current by its passage 

!n?ii, f co ‘ t io " sn ° ot d ' “• “ ^ 

wort™ b, H» wool current from 12 ' uf 0 “i “ 

tile coil 27 in min , 1 - r i 1 ° ma u cui ' rcnt passes through 

i.v.r, o«d an m«;vr2,L tho r„rfi K r" w °f tb ° 

which owing to sluggishness an,l i, ■ f , th ° rc P ontin S sounder g, 
not repeat the false signal on ’g. V “ B bC fully cllar S cd > &o., does 

puttolmo bv tl,„ tc , K S'i , “ d “» buttory-lli, 

would also, wore it not for thofoct tliatow'inc'toT 118 IU ^ 1 . tho l0VCr of M 
tho polarized tongucl moves a Konnn l • £ .° 410 rn P 1( My with which 

resistance coil E 7 and a battorv 7 ' C1 f ! “ lt . 1S closc(1 which contains a 
current passes through£t^ndtS tbat a 36 

through 27 from tho battery 11; hence the effftTJ *° ^ PaSSinS 
from that battery 11 is balanced in M. Wi Idn ffis * • ‘** ° Urront 
' unn tins equating circuit is 


Specification A.D. 1875.—N° 3S4. 17 

Miaou's Improvements in Multiplex Telegraphs. 

placed a relay Is, which oporatos a receiving magnot n, from whioh tho 
signals of tho polarized relay D, M, arc copied. 

It is obvious that tho current from the battery 11 will pass through 
tho coil 27 on magnet M before tho equating circuit can bo closed, and 
5 tho effect is to givo the lover of tho relay armaturo a quick forward 
movement, but tho effect of this is neutralized by employing tho repeating 
sounder g before described. 

In Fig. 13 tho polarized relay is dispensed with, and two separate 
relays used, both of which respond to the heavy battery, wliilo 0 responds 
10 only to the weak battery. M 1 and D are both adjusted with high tension 
of armature spring. Ono messago received upon M is indicated by tho 
sounder g, while the other message is received upon M 1 and sounder n'. 
The magnet D is used to close the balancing circuit to balanco tho effect 
of the largo battery within tho coils of M. Tho magnot M l might beJ 
16 taken out of tho main line, and inserted in tho balanced circuit h, R'ifl 
and produce the same effect. 

Another modification is shown in Fig. 12. D is adjusted to respond 
to the strong currents when the armature lever is away from tho magnet. 
The main circuit is completed which first passes through the coil of I), 

20 then to tho earth through a resistance of several hundred ohms in E*. 
Another route to tho earth is through shunt wiro u to armaturo lover 
of D, thcnco through point c 4 to the coil M on tho relay. In this 
position the relay responds to the weak currents from tho distant station. 
The tension on tho retractile spring of tho armaturo of D being great, 

26 and the cores somo distnneo from its armature docs not so respond, but 
when the strong battery is put to lino tho lever of D is attracted, and 
tho strong current instead of passing through tho coil M now passes 
through tho resistance E a and coil k ; tho effect of its passago through 
tho coil E a is to wcakon tho total curront nearly ns much as it was 
30 increased by addition of battery power, so that tho electro-magnet M 
docs not respond to strong curronts. 

Pig. 14 shows a plan, and Fig. 15 is a porspectivo view of devices 
tor magnotizing tho tonguo i of tho differential magnets D, M, and 
adjusting tho polarity of this tonguo i. This tonguo i is connected at 
35 one end to tho iron standard s, and contiguous to this standard s is a 
magnet t ; said magnet may be a permanent bar magnet, as in Fig. 15, 
or an electro-magnet polarized by a local battery » 8 , and tho magnetism 














A.D. 1875.—N° 384. 


Specification, 


Edison's Improvements in Multiplex Telegraphs. 


passes from t by induction through s to tho tonguo i, and honoo the 
tonguo i can bo more or loss strongly magnetized by adjusting tho 
magnot t nearor to or farther from tho standard s, or by adjusting tho 
rheostat E. " 

Mg. 17 shows connections similar to thoso shown in Mg. 1, with tho B 
exception of the magnet M and tho electro-magnet M, X, E, for 
balancing the ciTcct of the static charge and dischargo. Tho magnet M 
is provided with an extra magnet X acting on the opposito sido of tho 
armature lever, but with a tendency to move tho lover in tho same 
ice ion as . This magnet X is placed in tho condenser circuit and 10 
receives momentary magnetism at tho moment when tho current from 
the distant station is increased, decreased, or changed in the direction of 
tho flow. The object of this extra magnet is to produce a more powerful 

phenomenon of tho line. and 5f £ .“T* w° f th ° StaU<! 
circuit. When tho battery at that station! d 111 1 T° nd artificial 

magnet E, X, becomes noworfnliv i * , S mcnt ed or roversed tho 

upon tho cores of M l , X 1 sots one C , mi ’ Sedl and this ““gnetism acting 

within the triangular circuit in 8 momontai ’y induction current 
instruments M, and D, M contra,.vf rCSards tbo receiving 30 

lino, hence a balance is obtained and the ‘ StaU ° CUmmt fl ' om tho 
by the outgoing current. M X is l! i Mt ™ monts romai » unaffected 
tho two angular wires from being’ uneaual ° 1 ’f,? pUri,osc of preventing 
currents on tho passage of tho dfstanUurrent. ^ S ° ttiDS Up inductivo 

of groat olectro-statio “ 
may bo made so small, that a very 


Specification. A.D. 1875.-N° 384. 19 

Edison's Improvements in Multiple x Telegraph. 

powerful current will pass through It, X. Tho exact balance can also to 
obtained by moving tho magnot E, X, to or from M 1 , X 1 . 

In Mg. 18 tho same parts aro shown as in Mgs 1 and 10, except that 
tho tonguo i works to close a circuit from tho battery h to either of tho 
B electro-magnets It or «, and thoso move the reversing key E, K, similar 
to that shown in Eigs. 1 and 7. The battery B is connected with this 
reversing key similarly to that before described, honoo a chango of 
polarity in D, M, moves tho key E, X, first ono way and then tho other, 
and thus the message is relayed or repeated into a new circuit, tho object 
10 of this being to uso the duplex or quadruples systems before described 
on as long lines as convenient, and then to make tho magnets D, If, 
and 51, repeat tho messages automatically into now circuits extendin'* 
still further. 

Tho entire apparatus and connections for repeating as aforesaid aro 
IB shown in the diagram, Eig. 19, which although it appears complicated is a 
very simple, ono lino L for instance comes from New York to ono set of " 
instruments at an intermediate station, say, Buffalo, and tho other lino 
b, L, extends to tho distant instruments, say at Chicago, in tho other 
direction. 

20 The keys and instruments aro duplicated and exactly the same as 
shown in Mgs, 1 and 0, only there aro two distinct sot of instruments. 

Suppose that a message over the wire L acts by riso and fall of 
tension in the relay magnet 5r, and that tho message is repeated into 
tie sounder or receiving instrument g\ as before described, if tho 
26 snitch 10 in tho local circuit of the battery /' is closed the messago 
goes no further, but if tho switch 10 is open the circuit of tho battery/ 1 
extends to tho electro-magnet c, the switch of the key a being closed; 

defy the message received at 51 on ono line is repeated by c and IC 
in o tho next lino. So in like manner the messago received from Now 
01 'k * u tbo differential magnot D, 51, and repeated in tho sounder n will 
go no farther if tbo switch 12 is closed, but if tho switch 12 is open tho 
Messago will bo repeated to Ohicago at tho key h by tho magnet d 
ni K; that reverses tho circuit in tho samo manner as if tho 

ngor key 4 wore operated. Of course by closing tho switch 11 tho 
message coming over tho lino L, L, from Chicago and received in 51 
. c 1 '°l , oatcd to Now York, and the samo thing will occur in 
>' e alien to tho messago received in I), 51, from Chicago if the 


















20 


21 


A.D. 1875.—N° 384. 


Edison's Improvements in Multiplex Telegraphs. 

switch 43 is closed. Thus, ono or more messages may he automatically 
repeated in long lines without interfering with the working of the othor 
portions of tho quadruples instruments in cither direction from the inter- 
mediato station. 

In Fig. 20 tho polarized magnet D, M, and circuit wires arc tho samo 5 
as havo bofore been described, but the magnet M that responds to rise 
and fall of olcctrical tension is slightly varied. Tho armaturo 84 is 
polarized, and swings between the cores of tho olcctro-magnet M, and at 
the outer end tho tongue is between tho springs 82 and 83, and theso 
springs aro strong enough to hold the tongue stationary, except when 10 
the electro-magnet M is highly energized by increase of current from 
tho sending station; when at rest the current from the battery 85 passes 
by tho springs 82, 83, and block 80 back to tho battery, but when tho 
current is increased enough to draw the armature 84 towards tho 
spring 82 that is moved away from 80 tho short circuit through 80 is 15 
broken, and the current directed through the receiving magnet g, and it 
returns through spring 83 to tho battery, and if the polarity of tho 
current is changed and tho strength of current remains the armaturo Si 
flies over against 83, and moves it so suddenly that the magnet g will 
not have time to demagnetize by the momentary contact of both the 20 
short circuit springs with tho block 80.' 

^ Wtal I claim as my Imcntta and dcairo to sacra b, lottcra Paiaat 
tic «fault “ “Wl of toys that p„d„ooa 

T °P«>.cd by rise aad 

receiving iusiruments " 


Specification. A.D. 1875.—N° 384. 

Edison’s Im provements in Multiplex Telegraphs . 
rheostats, or induction coils to neutralize tho static charges and dis¬ 
charges, substantially as sot forth. 

Fifth. In a quadruplox repeater tho combination of tho two receiving 
instruments in ono circuit with tho two magnots and transmitting dcvico 
5 in tho other circuit, connected so that signals made in ono circuit will 
bo repeated to tho receiving instruments in the other circuit, and vico 
versa. 

Sixth. In a quadruplex telegraph a main lino circuit divided and 
provided with local batteries and circuits that operate tho repeating 
10 instruments, substantially as sot forth. 

Seventh. Tho combination in a quadruplox repeating telegraph of 
switches or circuit connections for dividing tho local circuits to allow 
each quadruplex line to work independently, substantially as set forth. 

In witness whereof, I, the said Thomas Alva Edison, havo herc- 
15 unto sot my hand and soal, this Sixth day of July, A.D. 1876. 

THOMAS ALVA EDISON, (l.s.) 

Witnesses. 

Cua*. H. Smitii, 121, Nassau St., New York. 

HAllOLD SuiUtELL, „ „ ,, „ „ 


LONDON: 

Printed by Oeohoe Edward Evhk and William Spottiswoodb, 
Printers to tho Queen’s most Excellent Mnjosty. 1875. 


i 











































[Second Edition.] 



A.D. 1875, 20Ui October. N° 3762, 


Autographic Printing. 


LET ™" ForT °/ N0 , Wark ’ in thc Stat0 o« Now 

Autogiiaphic PttlNTJNO.” ’ 0 1 Invontlou of " Imphovements in 

Sealed tbe 2Gtb A I )ril 1870, and dated the 2Gth October 1875. 


, u "“ sw » 
■ss^gfgi^aasas 

20 point that « stea( l of ink there is a noodle or 











Edison’s Improvements in Autographic Printing. 


as to make tho perforations very dose together, even with rapid movement of the 
pen. For this purpose I prefer to use a small magnet upon the top of tho stylus, 
actuated by a battery with flexible conductors, and tho armature opens and closes 
the circuit. A variety of electrical or mechanical devices may bo employod to give 
this rapid vibration to the ncodlo. b 5 

I remark that it is preforable to have the needle vertical, and provide a handlo 
at an indication to the stylus, so that tho handlo may bo held like a pon. 
arc?limi° e lj'| ra tb<i lettflr ? 1 ar0 m J ado by a type writing machine with koys that 
are depressed to compose the words, the type are to be composed of numerous 

arranged in the form of letters, so that the printing thorefrom 10 

perforates tho paper as aforesaid. 6 

The battery that I prefer to use is provided with carbon poles in porous cuds 
we u3f™ rC t h hT“ t0 °f p0taS } and sul P 1,uric “id, and the wrbon ancTzinc poles 

* » 



SPECIFICATION in pursuance of the conditions of the Letters Fatont filed by 
the said Thomas Alva Edison in the Great Soal Potent Office on the 27th April 
1870. 

Thomas Alva Edison, of Newark, in the State of New Jersey, United States 
5 or America. " Improvements in Autographic Printinq.” 

The object of this Invention is to print from a sheet of paper or other material 
that is perforated with numerous holos in lines forming the letters, numbers, designs, 
or other configurations to be duplicated by the printing. 

Tho perforations passing through the paper are filled with ink, preferably an ink 
Id containing glycerine and analine colors. Tho ink is rubbed into the perforations by 
a roller, brush, or other yielding dovico, and then tho perforated and inked paper is 
laid upon the shoet to bo printod, and pressure is applied sufficient to cause the ink 
in tho holes to pass upon tho surface of tho paper and produce a duplicate of the 
perforations; this may be done by the pressure of a roller that also serves to fill the 
*5 holes with ink for the noxt impression, so that by this means a large number of 
duplicate manuscripts can bo produced, and there is but little more work in 
proparing the original than in writing on paper. 

The modo of preparing the original sheet is similar to that of preparing any 
writton, or lettered, or drawn document or dosign. 

The writer or draughtsman holds a pen, but instead of ink there is a needle or 
point that reciprocates with very groat rapidity within a small tubo or stylus, and 
projects each stroko far onongli to pass through tho paper into some soft substance, 
such as cloth or blotting paper. The speed of reciprocation of tho noedlo is to be 
such os to mako tho perforations very close together, even with a rapid movement 
» of the pen. For this purpose I prefer to use a small magnet upon tho top of the 
stylus, actuated by a battery with flexible conductors, ana the armature opens and 
closes tho circuit. A variety of electrical or mechanical devices may bo employed 
to give this ropid reciprocation to tbe needle, 
on ^ remark that it is preferable to have the needle vortical, and provide a handle 
at an inclination to tho stylus, so that the handle may be held liko a pon. 

In cases whore tho lottors are made by a type writing machirio with keys that 
are depressed to compose the words, tho type are to bo composed of numerous 
needle points arranged in tho form of letters, so that tho printing therefrom 
perforates tho paper us aforesaid. 

The battery that I prefer to use is provided with carbon poles in porous oups 
containing terchromato of potash and sulphuric acid, and the carbon and zinc poles 
are upon arms that are elevated or depressed upon a standard; this furnishes a 
especially adapted to tho ropid movements of tho olectro-mngnet. 

,,. , .' 10 edges of the perforated Blieot are preferably hold by a frame whilo the ink is 
being pressed through tho perforations to the sheet below. 

In the Drawings,— 

Fig. 1 is o vertical section of tho pon or stylus in a form that I have discovered 
to be very convenient in use. 

45 ? I 8 a 8 ' do . v * ow of the actuating magnet, 

b ig. 3 is a section of the press as dosed, 
big. 4 is a plan of the same os open. 

Fig. 6 is a section of the paper bolding damp. 

big. 0 is a section of tho pen-holding stand in smaller size than the pen, Fig. 1. 

, big. 7 is a plan of tho bnttoty, illustrating also the flexible connection to the 
istant pon as in uso. 

Fig. 8 is an elevation of the battery partially in section j and 
big. 9 is a seotion of the polo-supporting catch of the battery. 







4 _A.D. 1875.—N° 3762. 

Edison's Improvements in Autographic. Printing. 

Tlio pen which I make use of consists of n tube a tapering to a small point b. anil 
n noedlo c within the tube, which needlo is reciprocated with great rapidity, and 
when the> noedlo point e is projected it is sufficiently long to reach through tho papor 
upon which tho tube of tlio pen rests, and when retracted the needlo is drawn 
within the tube, so that the small end thereof is free to be moved from placo to f 
place. The great rapidity m tlio movement of the needle point produces the 
punctures n the paper sufficiently close together to form lines whin the pen is 
ZT, T "' r ; tlng 1I 0r . d . mw 'f- m ! d ns notllin 8 ^ removed from the paper its 
strength is not materially injured by tho punctures or perforations. * 

It will be apparent that any suitable dovico maybe employed for reciprocating in 
tho perforatmg needle, several of which are hereafter described, but I prefer to use ° 
Bnd re v ? lvln e nrmature fly wlieel for this purpose, 
wheel f and 1 I3 1 U|,0n tho frame c that supports tho axis 2 of tho fly 

Sin D 4!V{ up™'Uie^axis ? so ^toota U ^ “ 

35Si“» 

standard o, ns in Fins 8 ami a „' y 110 atc ,‘ .* P'? ssi,, g ‘“to n notch in tho 


Standard o, ns in Figs. 8 and 0 TlZZ. “ 10 atc1 .* P? ssi,, g >“t° » notch in tho 
cylinders, is shown^ This constr^eZ ^ “■ ,n tho CuIls . m ar “ nearly half 

graphic pen, bocauso it occupies but little* <S V< ‘i™ t ' 0,,VBnient for this auto- 
brought into or put out of action P ‘ CB “” d " easil >' transported and 

sulphuriS Prefembly empl ° yed in the battery are tcrchromato of patash and ^ 

by mean^f which Ft° Mn^rclampe^aftS? 1 'tl*' 71 is , provided wit h a set nut 9, 
allow the needle to be drawn into *7° '" S )ecn adjusted, so as to 

aforesaid. aWn mto tllB ‘"be and projected by the motor, as 36 

the tube pen! and s^ppoluhllfamTand nroteet tf' 6 “7°/ ° nd * of a aize to receive 
within such stand. 11 ‘ d P roteot the point from injury when entered 

pen to be easil7moTed tb abou n t ^'perfta-mZ mI" 1 b ?.. floxibl «, as to allow the 40 
punctured should be placed upon some l" 8 '' f" d tho P a P<m to be 

to prevent injury tothe needle-point i„^ writinl SU "* C '° th 0r blBtt '»g P“per, 

^° a tullcr^pjflied'ta'tho'right^si'd^of^r 0 ^ * r* 0 fiU , tho holes ”ilh ink by 

:SSe r * rthatpr ^ tba '^ 

“ ”” “■ » d J * “»ip&r sr sji 


ft*''"*" 1 ''"- A.D. 1875_N° 3762. 5 

Edison's Improvements in Autographic Printing, 

turned over the edge of tho frame u ; a roller covered with felt or sin^' notarial 
and having ink upon its surface is now rolled over tho perforated sheet unt 1 aH 

nmdo by tho ink throush auch boi <» -A 

The hinged frame holding the perforated sheet may bo lifted for inspecting tho 

mpression, and closed down again if the impression is defective at any point 8 
Altar tho holes are filled tlio impression upon other sheets can bo mado in suc- 
cssion veiy rapidly, and a small quantity of ink is added from time to time 
Printers ink thinned out with castor oil may bo omployed. Anilino or colors 
nay bo used mixed with glycorino or molnsses. 

It is generally preferable to liavo the perforating needlo porpendicular to the 
paper and for convenience in holding the same there may be a lmndle a> connected 
nth tho pen tubo a, and occupying an inclined position, as shown in Fi". 11 
,{0 ? a ™° ob J c ®J “ccomphshed by the dovico siiown in Fig. 12: Tho perforating 
eedlo instead of being at the end of the red c is at the end of a short rod c' hat 
guided m the short tapering tubo b and said rod c‘ is connected to tho rod e by 
the lover it*. This nmingoment allows of tho tube a being held in the same 
^ pc^LutartotCpipor 7 held ’ and ° f maintainin g tb ° needle 

20 Various forms of elcctro-magnotic and other motors may be omployed to revolve 
the shaft that reciprocutes the perforating needle, and I will now briefly describo 
f « w of tho motors that may bo advantageously employed. y 

In Fig. IS tho holices d d\ are sustained in the frame e, and tho shaft 2 passes 
freely through them and forms their core. Upon tho shaft 2 arms / /‘ placed at 
i Zt an ,tV„ 0 T h ° tber ’ and u P on the frame c in line with said arms are metallic 

| ’ “ C 7 J. 8, 18, •? r """ K atatlonar y ‘“'matures. After tho shaft 2 is onco sot in 

I a dilk anirz. '? ° P °? 0d •,° loSed 7 tbo >'<*«* 4 d\ at the proper times by 

1 .mtt, cau"es t“na P / ,n /’' u “T, befora d ° SCribed - a “ d tho ™agnetic 

•10 ,.Z m i . 1 y f ' to . bo altarnately moved around towards their res- 
30 pictn o blocks to keop up a continuous rotation of tho shaft. 

thislZr .Zl'lTnr- 011 ° is , conn . cctt ' d to tho vibrating armature lever e‘, and 
a rcctmrtiln ““Z 8 7 m °uo <lirection by tho magnet d. and then in the other by 
i.rectructilo Bpnng, and when tho nrmature lever and needle-rod are drawn down 
35 anil th« B !i!™ E i ^^ , clrcu, . t chan g° r is moved and closes the circuit to tho magnet d, 
in ll a ™ at “f° lBvor 13 "‘uved upward, and in so doing moves the circuit clanger 
m the other direction and breaks the circuit, and so on, the circuit is opened 
^ closed, and thus a very rapid reciprocating movement is given to tho needlo 

« turon^sZZrl! 60 mt ninen0t - d ia , firn ! 1 J r “ ecurod 10 the shaft 2, and the arma- 
nnd Ilm ta . t onar F- There are insulated hubs or commutators upon the shaft 2 
"niSareTraZr Ctl M nS ^ tbe beIice3 d to tbo and contact 

one helix /iml Znll U3ual manner, so that tho current is sent first througli 
ini°n!7 u • d 1 T th < J tber ’ and a rotar y motion obtained by the cores of the 

45 magnet acta°as nlsy-yriieid th . 0 ... ar ™ atur0 /• B F this dB viee the 

In Tri„ in7i Uy iv' c0l ', and ,t3 weight is utilized, 
bv tlm 7 0 , nue ., °' r ? d o 18 connected to a vibrating armature lover e 1 moved 
tlenei,T,?7 U 7lr Prin ^ as in 14 i b “t a secondary magnet d> not Zn 
close mctulbo connection with tho magnet d, is employed to open and 

50 changor d« rCWt 4 ° ma g Det d b F actuating tho armature lovor d* and circuit 

and 1 el d ;n l C< tn 1 M Wn - in IT may be employed with equal advantage for opening 
is stutionarv l ° ® lrcu,t lo . 1,10 magnet cl. In said Fig. 17 tho electro-magnot 
latter in emnTl 6 tv es motion to a revolving armature and commutator, and this 
55 baltcrv tn 7,i *° a W ' tb ., t ‘° ° 1 0ntact s P rin g d opens and closes the circuit from tlio 
tiousl at tU ° Samu t,n, ° t0 tb0 lnns ' lefc tbB counec- 








6 A.D. 1875.—N« 3702. 

_ Edison's Improvements in Autographi c Printing, 

. J" 18 the nfdJo-rod c is connected a rocking lover e 1 that is provided with 
:i“ r0S ' an 1 h l “°. an “ of tL ° . C,rouit 0,iar S er e‘ operated by said rocking 
" " lover and the wire connections represented, the circuit is opened and 

JSf. S5 $&2z “ 8 “‘ * «* * »•“ . 

1° t ' 1 ®. neodIo . 1 rod c , is actuated by a revolving shaft and a cam operating * 
Jj? ‘ 8 ?| ock of Jbe needle rod o, as boforo described; but tho shaft is mado in two 
over life ° n ° part “ ido othor as the pen tube a is moved 

over t ° paper, and ono or moro baii joints are provided in tho daft /■ /» tonllow 
for still greater freedom in writing. The power to rotuto the shaft /> > j “1 
mumcated from a foot treadle by the link }• to a pulley/‘ wd from '.he 'latter a 

“^SoES: tho shaft ^ - w«^ e tKu 

from Oio vessel A«-to replenish the supply in the voM l ° tUn9 

said, tho pawl turns the ratchet wheol i* Ld shaft 2°Ind fctfl “1 08 afom * 

keep tho motion regular, Q BUalfc and fc e w ^ e ®l ** serves to 

,i e, x •?,«»■*- »•—»* 

table as the pen tube is moved over tho^innnr ?r' an ^ wheel rolls upon the 
Im-ge pulley V and from 7aTeft lad s P to a 37 Me ? tI, ° wlleo1 ™ 4 » a 
gearing the motion is finally transferred 5 uI, Z TO "* oud b y the bevel 

sufficiently broad and heavy to stand unricht Mrl nlfi?' i-Vl* ,"’ lieel m ‘ sIlould ba 
In Fig. 23 tho needle rod o is connected to • b ! J 0 li P «*er. 3 

armature to the eleetro-magnct“ and wl,en a ., tbm . mo ‘ a| b° Plato that forms the 
attracted by the magnet, thTplato“ closod ‘bo plate 
thoe !ti * he spring of the plato iJ£iodiatelyraisMTLm^ ^ and breaks tlla 
tho circuit, and tho plato and needle-rod are aZin 1, f , “'r® Dm 8 n0t and closes 
cu-cmt is opened and closed and a verVr an fd m nvI“ ( ° U ? ht do "' n - a,ld 80 tho 35 
% 24 illustrates how letters S B “C2 6<von to tho neodle-rod. 
m the paper. A lover o 3 for each lotto, ““ ordinary types may ho punctured 

represented to Fig.^'l^hav^how^ *v 9dl9 , p ? int8 ' mi 8 bt be upon a wheol as 45 
turned’ 14 Tho S Kg • P ° n *•>**•«* 50 

ussa-SSsSiSSar-. 


sped**"'". A.D. 1875.—N° 3762. 7 

_ Edison's Improvements in Au tographic Printing. 

Second. Tho portablo perforating instrument for writing or drawing composed of 
a tube or stock with a small end similar to a pon, and a perforating needle and 
means for reciprocating such needle rapidly, substantially ns set forth. 

Third. The method horein specified of printing in pormanont somi-fluid ink by 
5 puncturing a sheet of paper or similar material with numerous small holes, filling 
such holes with a semi-liquid ink and pressing tho same upon tho surface to bo 
printed, substantially os set forth. 

Fourth. Tho swinging frame u and paper holding clamps 13 in combination with 
the bed t for recoivmg and holding tho Bhoot of porforatod paper, and the sheet to bo 
10 printed, substantially as sot forth. 

Fifth. Tho combination with tho revolving magnotio motor, pon holder a, and 
puncturing needle c of the cam dr, having three or more points, substantially as set 


Sixth. The combination with tho portable hand perforating instrument having' 
15 ® n t ^ ectro ' ma 8 netlc Inotor o£ n flexible conductor and a battery, substantially as sot 

Seventh. Tho portable galvanic battery composed of cells in a stand with a polo 
supporting rod, latch, and cross head, in combination with floxiblo conductors, a 
magnetic motor, and a perforating pou, substantially as sot forth. 

20 _ Eighth. The ink herein specified for autographic printing composed of printors’ 
ink thinned out with castor oil, as set forth. 

Ninth. Tho pen tube a provided with tho handlo a 1 in combination with tho per¬ 
forating needio and electro or other motor for actuating tho same, as set forth. 

Tenth. The needle o' guided in the short tube b l and connected to tho rod c by 
23 the lever a 3 in combination with the tube a and motor for actuating the needle, sub- 
8tantially as and for tho purposes specified. 

Eleventh. The letters or characters for a type-writing machine mado of needle 
points for puncturing papor or other material for printing, as set forth. 

In witness whereof, I, tho said Thomas Alva Edison, have hereunto set liiy 
30 hand and seal, this Third day of April, A.D. 1876. 


Witnesses, 

Cha>. H. Smith, 121, Nassau St., Now York, N.Y. 
Qeo. T. Pinckney „ „ „ „ „ 


LONDON: Printed by Gkuuuk Ehwahii Etub nnd William SromswooDB, 
Printers to the Queen’s moat Excellent Majesty. 

For Her Majesty's Stationery Office. 
[ 19638 .- 50 .- 3 / 80 .] 























































A.D. 1S7G, -16th.I lly. N"30J2. 


Acoustic Telegraphs. 


(Thw Invention received Provisional Protection only) 


5 It is well known Unit if two burs or forks of steel of equal length, braultli. ami 
thickness ho secured nt one end and properly adjusted they will vibrate at tho 
same rale of speed, Heeds of this kind linve been used in telegraphs. 

I have availed of tills well-known operation to construct a peculiar telegraph 
that is capable of being used either singly, one instrument nt each end, or two or 
10 more instruments at each end of different tones or pitch, so that the instrument nt 
one end energises tlio instrument at the other end of corresponding pitch. 

Tlie Invention consists of two acoustic reeds, tuning forks, or ollici bodies 
following the law of the pendulum, operated directly by elcctro-mngnetism or 
indirectly by the intervention of sonorous bodies or columns of mr between sulI 
15 reeds, tuning forks, or other bodies following the law of the pendulum and the 
electro-magnet; such electro-magnetic acoustical reeds are placed at the two ends 
■ of a telegraphic circuit, and being provided with contact breaker points, pitches, 
connections, and other proper devices, vibrato when properly ndj ’.sted m pci tea o 

magnets operating such reeds are placed upon a new set ot electro-iiuigacts entire y 
disconnected from tho reed magnets at botli ends of the u no sinudtiu cously at 
25 that particular period of time when the wire is not transmitting “ “ 
wave. Tho second set of electro-magnets contained m a branch e «uit at both 
ends limy he common Morso relays operating sounders and controlled by a toy, 
the t W o receiving tho same number of waves ns the reed but not at tlio samo time, 
and occurring with groat rapidity act upon tho relay in tho samo manna as n 
30 constant current. « . 

The Invention further consists in peculiar contact points to casin o a perloct 
transfer of tho wave from tho signalling instruments to tho reed i t u ei Is 1 







Edison's Improvements in Acoustic Telegraphs. 


Tlio Invention further consists in peculiar forms of roods and olcctro-mngnets 
operating the same to suit tho various conditions which aviso upon long, short, and 
inferior tolographie circuits. 

Tho Invention further consists in tho mothod of compensating for tho mutilation 
of tho acoustical and signalling waves by tho static current, and by derived currents 5 
from contiguous wires. 

Tho Invention further; consists in the mothod of transferring tho main wire from 
tho acoustic magnets and circuit at terminals and at way stations to tho signnlliii" 
magnets at tho snmo station. ' ! " 

Tho Invention further consists in tho method of trai fe 1 ng tho signals from one 10 
circuit into another. ° 

The Invention further consists in tiie method of transferring tho signuls into 
branch wires. , b 

The Invention further consists in tho mothod of duplexing and nuadruploxing 
the signalling circuit obtained by acoustical transfer. " 15 

Tho Invention further consists in tho method or transmitting two messages in 
tho same direction upon tho circuit obtained by acoustical transfer ° 

Tho Invention further consists in the method of signalling (upon tho circuit 
currents^ ^ ac0uaticn trai,sfo1 ') b y tho uso of polarized relays nnd reversed 
The invention further consists in the method of transferring several separate !<> 

*—- f “ — * ss 

distinct messages in eitlier direction at the same time 
Tlie lnvcutiou further consists in tho method of regulating telegraphic machinery 

mission o™ol%rarns > over tlio^samo s °' n ^ S tfi *' 0 bno ° bl co miection with tho trails- 
Hussion 01 telegrams ovei tlie same wire nt tho samo time. 

Hie Invention further consists in the mothod of transmitting messaws ,™n tl,„ in 
relay instruments which servo to Jmf +L |a i° I 1C te *®g n JP« lc wlro acoustical 

ijfr TH,"of Ml "3 tr""'!?""" I *™ll of tho tuned ’’ 

nnd contact devices upon the reeds sw ,d„,r S * , 111 a tclcgraphio circuit 

telegraphic lino, tliciXkcmtaTbo1,«££ n ""■} close circuit of such 40 

^EeSH^ I; s= 
ssysfe ,t,:s sssi sstr ”? •S? “ 

the line. Connected to thoseforksnro«mt»S . a y nchr °“°>>« 1 y at both ends of 45 
several split circuits in which are rdnml ” * and s P n,, S 8 arranged with 

teing fhi same it both ends of the lino and ,el . Tll ° connections 

and springs at each terminal is connected L„L f w , ks ““‘I, 11 '® 11 ' contact points 
The synchronously moving local reeds scrviim , V "“other tolographie lino, 
one sot of signalling instruments trans or suoh telegraph lino from 50 

one after tho° ot!,or°wHl, mS^mpiditv bu^n -T™ 1 ° th ° r se , ts of instruments 
is never upon more than two sets of siennllim? inntr!,ni .T",''!, tlat 41,0 Inain 11,10 
several messages maybe transmitted 3 lnstrum( : ntf * at tilie samo time, lienco 

tune There maybe included withinttio samt locXol™ ? t prac4ica,1 y nt tho same 


several messages limy bo transmitted XwH ' nstrum( : nta at tho snmo time, lienco 
tune. There maybe included within tho immlln™? 0 . Wlr0 . Practically at tho same 
transfer forks which may servo to transfer nn< J fcbor set of nconstical 55 

several sols of signalling instruments^ 


Edison's Improvements in Acoustic Telegraphs. 


I'laeh one of tho branches or splits so obtained nnd upon which signalling takes 
placo may bo arranged with a Wheatstone bridge, equating resistance condenser, 
or electro-magnet, tlio last two for balancing tho static charge of tho lino so ns to 
allow of tho transmission of two messages in opposito directions at tlio same time 
5 upon cncli split; with this nrraugoment I innko uso of circuit preserving keys. 
In practice I prefer to use polarized receiving relay circuit preserving and reversing 
finger keys for signalling. 














A.D. 1877, 30 th N° 2909. 


Controlling by Sound tho Transmission of Electric Currents, and 
the Reproduction of Corresponding Sounds at a Distanoo. 


LETTERS PATENT to Tliomns Aiva Edison, of Monlo Park, in tho Stato of Now 
Jersey, United Slates of America, for tho Invention of “ Improvements in 
Instiiujirnts koii Controlling uv Sound the Transmission of Electric 

CURRENTS, AND THE REPRODUCTION OF CORRESPONDING SOUNDS AT A 

Distance.’ 


FR0 O(TW°?o Ij SPECIFICATION loft by tho said Thomas Alva Edison at tho 
wince ol the Commissioners of Patents on tho 30th July 1877. 

Thomas Alva Edison, of Menlo Park, in tho Stato of New Jersoy, United States 
5 TraJ“„ Is J™ 0VKMENT in Instruments for Controlino by Sound the 
Sounds at a Distyncf’’ 0 CtmnENTS ’ and ™ e Re ™oduction of Corresponding 

° f tbo nt mosphero, which result from tho liumau voico or from 
the e"ec , ;, f“ stniment w otherwise, are made to act in increasing or lessoning 
10 lc-eninoVhn • ,°° Up ° n a lno by °P 0Ilin g or closing the circuit, or increasing or 
at tho LT- ml "Ty ° f contnct between conducting surfaces placed in the circuit 
a vibration' 1 " 8 , 11011 > tl10 electric action in ono or moro electro magnets causes 
a soun.l i tynpan, or other instrument similar to a drum, and produces 
discovered tlmf ti"“r™ 1 . is erently augmented by mechanical action. I have 
15 proper]v nrntti i , fn “ tl0 “ ° f 0 P 01I >t or surface that is in contact with a 
by the strunnH, r it , w, y moving surfaco, is very much ineroased or lessoned 
variation in ti,“ “>« oloetrio wavo passing at such point of contact, and from this 
or means that „Jn"i° t,0n a F ea , t<5r or less vibration is givon to tho mechanism 
• renderinn dent ?Li “??,?' dovolo P a ‘be sound at the receiving station, thereby 
20 audible. 8 10 ano distinct tho sound rocoivod that otherwiso would not bo 

P eoulia rities o£ my Invention under tho varying conditions of 
intensifying (1 °°y iae(1 several modifications of tho transmitting, receiving, and 
[P '81 V ' 8eS ° mp,oye<J in tbis so u n d telegraph j portions of tho apparatus 











2 A.D. 1877.—N° 2909. gjjgjjjju 

Edison’s Impts. in Controlling by Sound the Tran smission of Electric Currents, &c. 

nro interchangeably, avnilnblo in transmitting or recording; otbors nro adapted to 
local nso; some are only avnilnblo in transmitting, and others are only for rocoivin" ■ 
and some portions of my improvement enn bo availed of to innko a rocord of the 
ntmosphorio sound waves, or of tbo electric waves, nr pulsations corresponding thereto 
or resulting thorofroin. j 

In ouo form of my apparatus tbo sound passes into a resonant box bavin" one 
fc\vo, or inoro tympans nfc its sides tlmfc arc vibrated thereby, tbo tension of* these 
being various, so as to respond to difTcront sound waves, and tbo electric connections 
pass through all to one line or circuit, in which is a battory nnd the distant 
receiving instrument. Circuit contact points are provided at one or both surfaces 10 
of the tympan or tympans; the tympans me of parebment, foil, mica, sheet metal, 
or similar nmtenal. I find platinum, foil, or mica to respond advantageously when 
the waves iron, tbo mouth are made to pass tl,rough a slot resembling the larynx 
placed with,,, the resonant tube. Tbo contact points or surfaces are sometimes 
metallic, but plumbago, or Binular semi-conducting matorial, into which tbo tymnan ” 
or (liaphiagm is brought more or less intimately into contact, or a point or pin 
tnoreon serves to lessen or increase the electricity passing at that point 
aaoltoZ!!? portion of tbo instrument the tympan is,acted upon directly by 
" r th . ro "v rh nn armature, or the tympan is provided witl. an arm 
p'assintr at tbo nnint'nr °"' y "J°y in o surface or cylinder, and tbo electric current, 2 
vibration of ‘the nm “i t" ' '" CIC! } SC * or leS!i0ns 1,10 a » d produces tbo 

or paper; the tnuismitting^ointTh/ah^ 

,,r “■ ” •“' 

winch ^increases and decreases its resistance. 1 ° 01 similar matoiial, 

from the vibration’ oniioVmp™"uid 'male 1 ] 011 ^ wil1 rocoivo n motion 

plumbago point without arresting the ,! „ ? °, r IoM Int " nato contllc t with the 

from tho movement of the tvmnnn n i 0 ectric te,,s,on will result accurately 

““ *■ 

IS vibrated or undulated by tlio sound waves°notin n<1 to , tlK!t 5' m P lln at tbo other, 
greater or less contact with nieces of tin tvi° S n0tln S °. n t ' 1 ,° tympan, and produces 
electric circuit or plumbago- co ta t n'i^ 1 it, which also are in the 

same object. A column fonnedofdisksoftb! Wl!‘° Sul ? of 8u , ch B P»™g effect tbo 50 
the vibrations of the tymnan also nm ln a fi Ias s tube, pressed upon by 

regulate the electric tension in the circuit. ° mpl0y0d " Ud0r 80,110 ’ciremnsta,ices to 

cessation °f'"^ 8 oureent^foixaaid^bTomnhnM? 0 ^ 01 ' docr .°' ls0(1 “Pen tbo passage and 
electric and mechanical acS a frame Tsl S ° m ? 1,ls i“ n003 to vibrato by the 55 
musical sounds, or to give motion t^reeds^r^osonant^boxos. 1011 ^ pit ° h ^ 


A.D. 1877.—N° 2909. 3 

Edison's Impls. in Controlling by Sound tho Transmission of Elcdrio Cur rents, <te. 

Tlio transmitting tympan is somotinies mado of cloth, with plumbago pressed into 
its surfaces, and generally it is preforablo to woiglit tbo centre of tbo tympan, and 
tako tbo motion a Iittlo ono sido. of tbo centre to prevent a flaso inovomont or 
rebound. Tlicso sound transmitting and receiving instruments aro applied insiuglo 
5 or multiploy telegraphs; tlio connections through tbo Wlieatstono bridgo, or tbo 
imluction coils, being used in tbo woll known ways, and tlio circuits being cither 
single or relays. _ 

Where nlluminium is introduced in tlio olectric circuit in connection with a 
material containing an olcctrolite, tbo vibration of tbo tympan, nnd an extension 
10 from it to thu material containing tlio electrolyte, causes a depolarization at tho 
point of contact at every vibration, thus increasing and decreasing the strength of 
tlio current by depolarization. 

Where a slot is limdo in tbo diaphragm, and tbo airways impingo against tbo 
same, the vibration of tbo hissing sounds is augmented. 

15 The resonant chamber for convenience is made portable, so as to be presented to 
tlio mouth., 

In addition to tbo tympan for transmitting the vowel sounds, I employ another 
opening in tbo speaking tube or chamber, which opening may bo increased or 
lessened ; I stretch edgewise over this a thin reed of foil, which is set in vibration 
20 by all hissing consonants, nnd mako contact with a plumbago point, or with a 
platina point, which is connected to tlio lino through an adjustable resistance coil, 
or a self-acting reed giving a hiss may be thrown in and out of circuit by tho 
inovomont of tlio foil reed. 

For transmitting nnd receiving letter by letter, I employ a shaft with 30 wheels, 
25 and contact springs resting upon them ; tlio wheels aro provided with teeth of such 
number and character that they will cause the springs to be vibrated against a 
plumbago point tho necessary number of times, und with proper pressure to 
transmit tlio letter, which is rendered audible at the distant station by tho magnet 
or frictional surface. Each wheel is controlled by a key of a key board. 



















Edison’s Impts. in Controlling by Sound the Transmission of Electric Currents, 


Sounds at a Distano™ ' andt,ik r ^-iioduction of Corresponding 

-zs c.rsr; 

st“; 

speaking into a resonant caso to urndn™* 1 ?‘ VCU ^°r ?, d ' n P hrn g'. n or tympan, by 
the lino with such accuracy that tho clnntri'nY'T- fa of clectricaI tension upon 
atmospheric sound waves pro luce] bySE£ T , W| Wa T» WiU ro P resonfc ‘ ho 20 
receiving station will id t d S° ^ ^ electro-magnet at the 

Thein:tr by , 7 li ''Z u Po>' atson^ pLt^ 8UCh “ “ “ to 

a section of the transmitTing iUramentrand^^o/tlm If' * “ d - 2 ’f ig ' 1 boing 
The resonant tube or box a is of a 7 i ?' “ f , 0 ,ecclvm g instrument. 25 
the same having an opening at ono end or siiln'o'lwV^ a f u I >f ; ed to bein g .spoken iuto, 
against which tlio sound waves from f|,„ i d 11 < . la P bnl g m or diaphragms b, 
motion that the diaphragm ffin m ™ mBn » V0,C0 , " 0t ' and thoso and the 
electric tension on the lino bv tho dov!™» h o ° f l ), ? duc,n g a riso and fall of 
connected to the lino l will transmit a SCt foi ' tb * 80 that tll(! battel 7 B 30 

magnet m, Fig. 2. and increase or lessfn thl Z ^ to tbo distaufc electro- 
doing act upon a resonant pl„ e „ ,, ma S notls "> of the cores, and in so 

articulation at the transmitting P station ’ d ° P 80und corresponding to tho 

J-iio general features thus desmlwl „„„ , 
developing tho same many useful ,iSmEST** ?? enliro Invention, but in 35 
keen made, which I will proceed to set fo?th mod,ficatlons a “ d variations have 

and flexible Conductors fo k f he battorv^S^' ia P roviduJ with a handle a\ 

bandied and brought to the mouth and bUikoT rCS P cati . vel y- s ° ‘bat it may bo 
“ d L tba resonant plate touching the ear incrcaC™ ° r f? t,1B "e^nsCf bearing, 

Tlin fi£f ra ° nS ° r , fcbo P’noes. bX ° d r ° SOnant tube - those being variable to 
tbo resonant tutoVth^vdca Cfave S ” 10 oon " idorat ion is tho peculiarity of 
b 08 r d ° f ‘ 10 l,issin ff consonants such X r„ l,e I 1 1 ?. ud great '«««% in reproducing 

sasss mmm: 


jpoHtaiion. A.D. 1877—N° 2909. 5 

Edison's Tmpts. in Controlling hy Sound the Transmission of Ekelrir. Currents, do. 

arc given either to tlio resonant tube or deflected to tho diaphragm. 1 find it 
preferable to employ a hole « at the lower part of tho mouth piece, against tho edges 
of which tho downward sound waves are directod. Tho snmo oflect will bo pro¬ 
duced by a vibrating edgo placed in tbo lower part of tho mouth piece, or tho 
5 opening into tlio resonant box may ho contracted to about half nn inch in diameter 
to effect the same purpose. The nuxt feature requiring consideration is tho ohnrnctor 
of tlio diaphragm in tbo speaking instrument. 

Many materials have been omployed by mo, such as metals, horn, vellum, celluloid, 
ivory, &c„ but almost all of thoso produce a prolonged or secondary vibration from 
10 their own resonant character, lioneo tlio articulation is defective, and tlio sound 
vibrations blend. After oxtonsivo experiments I find that mica is almost entirely 
free from any resonant action, and hence it will respond with the greatest accuracy 
to the sound vibrations, and being of a laminated character can be omployed of any 
desired thickness, and when secured at its edges responds with tho greatest 
15 accuracy to the sound vibrations, and does not require to be strained j furthermore, 
the changes of temperature and atmospheric condition liavo little or no effect upon 
the mica diaphragm or tympan. 

1 find that it is not practical to opon and close tho lino circuits in instruments 
for transmitting tbo human voice; tbo circuit to the lino must bo always closed, 
20 and tho transmission be produced by a rise and fall of electric tension, resulting 
from more or less resistance in tho line. This rosistanco may bo produced in 
several ways. I have shown soverul which will hereafter bo named, but I find the 
most delicate to bo sinnll bunches or tufts. Or disks of semi-conducting elastic fiber, 
such as particles of silk, and an intermediate conducting or semi-conducting material j 
25 this device I call uu electric tension regulator; it is more or less compressed, according 
to the vibrations of the diaphragm or tympan, nml tlio electric current rises in 
tension as it is compressed or lessens as tho fiber expands. 

This fiber is placed in a small roll t, between the delicate diaphragm spring u, 
Fig. b, and the variable pressor v, adjustable by screw or otherwise in tho electric 
.10 circuit at this point, or it maybe within a cavity in said pressor v, as in Fig. 1, there 
being a delicate cork center picco w to the diaphragm b, with a piece of platina 
foil x in contact with the fiber; in all instances the telegraphic circuit at tho 
diaphragm is made by a thin strip of platina or similar material extending to tbo 
center from tlio lino or battery connection. 

35 ll.o fiber is rendered semi-conductive by being rubbed with plumbago, soft 
metal, or similar material, or by a deposit of metal upon its surface, or by fine 
particles of conducting or semi-conducting material mixed with it, tbo conducting 
power varying with the density of the tuft or bunch of fiber. Tho delicato spring u, 
Fig. !), upon the mica diaphragm b is easily secured by' solder passing into fine holes 
40 bored in tho mica. 

In Fig. il tho tension regulator is made by water or other semi-conducting 
electrolytic fluid in a ciqi /. Tho wires to tho battery are led to the olcctrodes or 
conducting points 2, 3, in such cup that aro opposite to points 4., 5, upon the 
I _ dinphrngm b. 

45 Tho cup is adjustable to vary tbo distance between tho electrodes nnd tho riso 
and fall of tension results from the varying distanco between tho electrodes ns moved 
by the vibrations of the dinphrngm. If tlioro arc sevornl olcctrodos opposite to oach 
other and insulated, oxcopt at their ends, and the circuit led from ouc to tho other 
60 font the current passes through all tho ulectrodes in succession, tho riso nnd fall 
50 of electric tension will bo promotod, because tho smallest vibration of one set of 
electrodes is multiplied by tho number of places at which the motallic circuit is 
interrupted or varied. In tho receiving or hearing instrument the resonant plate c 
should bo of tinned iron, resting upon tho odges of the caso, and tho inngnot m, 
.. “djustuble nearer to or further from tho same, and connectod loosoly by slotted 
“ii tongues, This pluto will respond to the electric pulsations by tho attraction of tlio 
magnetized cores, and tho sound resulting will bo audiblo when tho plato is placed 
near or against tlio ear. If tho pinto is pressed away from tlio magnet by a delicato 












_A.D. 1877.—N« 2909. 

Edison's Tmpts. in Controlling by Sound the Transmission of Electric Currents, .Cu 


27 fi ' 0m r' le T"'" 0t ' th0 “‘^rumont nmy bo used,« a coll 


this will produce greater rise and fall of tnnJL r °\ S be,,, ff .°N ,n the electric circuit; 
diaphragms acti n | si „ lu lS^^S; " los “ ““"l" 0 ™* ° f «•• 
is preferable to make tho mouth niece of the . t 1,1 som « instances it 

ser “•“»■> va^^zsjtaissa,j2!:» 

need, th« enmoXtinghf Xu ...7" l ° X ; ,iapl “' ,l S" 1 ' m "> Ll > 

rlz uT'iS;,",;? s s,-; 

cncuit, but the movement of the dinnhramn >r "F m ' "l acrvu to limintnin a closed 25 
tension regulator, formed ofateTiS^r I,S . e and , f “" «f tension. The 
bo either dry or moistened with a linuW ‘ S som, - con,Iuc tmg material, may 
in some instances I innko hr* i* , 


In some instances I mako hr* ^ 

case to form the tension regulator tbo rimd? U<l °n Iam P bIack wtninod within a 
and fall of electric tension resulting from tho J'"; SSII, o t l ,rou fij' , tIie Sftn *°. and the rise 3 
merit of tho diaphragm. g Ul ° compression of the same by tho n - 


wise by causing the movements o^ thedinrfXfTt ^ ‘ Uman V ° ic ° ° r otl ' 01 '- 
Bheet metal, and then tho paper may bo used b f r 'S ,sltrcl ' on paper or soft 
sound upon a delicate diaphragm by Iw a , instrument to reproduce the 35 

°L Vibmt j° n *.««' MiKAE ^ 

rates «T°V ,m ‘ ,er "fter beingMenudh““ d ^“'S *«HmUoi 5 of the 
ratus n, Fig, 5, almost similar fn l. . ,luc . mea is passed through a second anna. 

If theso sounds ’ ” U i ,roJuces previous 

descritfn ?' /" telegraph lino the diaplmmm 10, 511 

“S3"" a r p1 '^ 

g a point or points resting on tbo 


SpocilUiton. A.D. 1877.— N° 2909. 1 

Edison’s Tmpts. in Controlling by Sound the Transmission of Electric Currents, Sic. 

paper; this arm is connected with a resonant diaphragm, and the ink marks produco 
moro or loss friction, according to tbo breadth and amount of ink deposited, and 
this will set tho diaphragm of n vibrating, and reproduce the vibrations of tho 
diaphragm of h. An obvious modification would ho to coat tho paper with a sub- 
5 stance which would cause considerable friction, or evon rough unsized paper might 
bo used, and a spring provided with a burnished point, rather flat, would oauso tho 
surface of tho popor to bo made smooth moro or lo.ss, according to tho vibration of 
tho diaphragm, and tho differences in tho surface of the paper would produco a 
response in tho recoiving diaphragm. 

10 I sometimes arrange tho battory in connection with tho transmitting instrument, 
as shown in Fig. 10. h is tho resonant chamber at tho end of which is the 
diaphragm 10, and nt oacli sido of this diaphragm there nro springs c 2 , <?, having 
points made of compressed plumbago mixed preferably with gum rubber, but any 
_ substanoo not lioblo to rapid decomposition, or tho elastic or fibrous tension 
15 regulator aforesaid may bo used. Those points face oacli other on opposite sides of 
the diaphragm, and mako contact with platina foil disks secured to tho diaphragm. 
The spring c’ passes through a hole or small slot in tho sido of tho chamber h. 
ip, d\ aro tho main batteries. The battery tl 1 has zinc to the line or spring c 2 , and 
tho battery «P has copper to tho lino or spring <f. When the springs c- and c 1 aro 
20 adjusted to mako contact with tho diaphragm equally, no current passes to the 
lino; hut when tho diaphragm is vibrated, its movement to one side, say c 2 , causes 
a greater pressure upon tho plumbago on that spring, and a lessening of tho 
pressure on the plumbago on c 3 ; lienco tho balanco of tho batteries c 2 and c' will bo 
destroyed, c 2 , having tho advantage, will send n negative current to lino ; upon tho 
25 return of the diaphragm tho battory currents will again neutralize each other. Tho 
vibration of the diaphragm to tho other side causes tho pressure to bo reversed, and 
the buttery iV * will send a positive current to the line. As tho tension regulator of 
fiber or of plumbago decreases and increases its resistance enormously under slight 
changes of pressure, it follows that tho strength of the electric waves will bo in 
30 proportion as tho speaker’s voice is strong or weak. In Fig. 11 is shown tho 
contact spring, which inay bo used adjacent to the diaphragm at one or both sides 
thereof, c 3 is a U shaped spring secured to the screw c 4 , which is adjusted back 
and forth by tho thumb nut c*; e* is the pillar holding such screw; r is a piece of 
_ rubber, or equivalent substance, placed between the prongs of the spring c 3 ; 
35 c is a wire or band which serves to bind the prongs tightly against the rubber r, 
so as to prevent tho prongs acting as a tuning fork, and transmitting harmonic 
vibrations not de.sirablo; r 2 is tho plumbago contact point. The object of the 
U spring and rubber is to present a semi-rigid point for contact, so ns to prevent a 
rebound, and allow of a slight yield when tho plumbago is pressed by the 
40 diaphragm. 

In Fig. 3 the diaphragm of tho receiving instrument is vibrated by a strip of 
paper chemically prepared that is in motion, tho pulsations of electricity passing 
over the line and producing moro or less friction between the paper and an arm 
upon the diaphragm. The resonant box or chamber n is provided with a diaphragm 
ns aforesaid, and to said diaphragm an arm Jr is connected ; at its outer end is an 
adjusting screw h*, that presses upon a platina*faced spring h* that is secured to 
tms arm, and said spring rests upon the strip of paper that passes over the drum h\ 

1 nc, paper « moved slowly by rotating tho drum A 8 , and the waves of electricity 
50 n° lm,, *i ovor tl,e Km* pass through the arm h? to tho platina-facod spring k\ thence 
V”' ou g“ the paper to tho .earth. If a negative current passes in the opposite 
direction, nearly all friction between tho platiuu plate and tho paper ceases, and the 
diaphragm of tho resonant box n regains its normal position. When the positive 
current passes through tho sumo channel, tho normal friction of tho paper is 
55 l r ?? mcnt ®d» the chemical surface acting upon tho platina spring arm serves to 
give a forWiird movement to tho diaphragm of tho resonant box. Thus tho 
acchanical forco applied to movo the chemical paper or surface acts with the electric 
rrent to produce tho vibration of tho diaphragm of tho resonant chamber, and 









Edison's hnyts. in Cmitroiliny by Hound the. Transmission of Electric Currents, du 

tlioso vibrations will correspond to those of tlio diaphragm 6, mndo by speaking in 
tbe tube a. Tho principlo of tin's method of obtaining motion by uloctro-cliomic.nl 
decomposition is, tlmt when n moving surface is in onntnet with n slightly yielding 
substnneo, the tondunoy is to move tho Inttor by mid with tho former. If tho 
circumstances of contact m o varied, tho adhesion of tho surfaces will be snfliciont to 5 
causa tho moving surface to move tho yielding subslaneo, nr else to cause tho 
yielding surface to slip more freely, and by its spring go in tho opposito direction to 
tho moving surface. Tho passago of electricity at tho surfaces in eontaot will 
change the frictional adhesion, making it more or less, according to tho substances 
employed. . 

By balancing tho mechanical forces, so tlmt when tho surfaces in contact nro not 
electrified, tho moving surface carries with it the yielding surfuco; and, when 
electrified, the yielding surfuco slips back over the moving surface, a mechanical 
movement is obtained that is dependent on tho electrical condition of tho surfaces 
in contact. , j. 

When it is requisite to obtain very perfect articulation, and when loudness is not 
essential, I adopt a modification, shown in Fig. 12, of the dovico for compressing 
and expanding tho tuft of conducting fiber, which modification consists In phioiim 
between the diaphragm 10 and the,fiber t a vibrating tongue 21 of steel, permanently 
magnetized, and arranging it to act in the same manner upon tho tension regulator l 00 
as it it was the diaphragm. I replace the cork upon tho diaphragm by a thin 
armature of iron 22 which is in closo proximity to the magnetized tongue, which 
tongue is secured at one end like an acoustic reed. In this position the dianhramn 
rnos!. 0 and at its approach to and recession from the magnetized tongue 

causes said tongue to follow its movements by magnetic attraction, and thus the ‘>5 
. . "■ 

A iiiodificntion of ihe magnetic e iv 1 „ 1 t e t 0 s ts 11 an 101 nlato 
titled into Uic aperture of a resonant tube, and secured by a central support leaviim 
1 s ou or tsrcunifertuice free to vibrate when the metal is attracted by the’poles <d' •;() 
tho electro-magnet, which are of course on each side of its center • l„ it is 

wilfthe^,°h° in Ift tone ll fo S ' ,PPOrt ^‘i^ ° A Ut C °" tc ''’ "" s0,n,! of tho plate 

i'ts cih'cs when*nhuwHn 80 V 1 . 111 A plate supported eccentrically and free at 

. . ;! "fi 

currents of I g i 1 producing changes of temperaturo will cause 4« 

over the line l ami acting !„!! 11 ^ Wlt , 11 !! tI,e thermo-battery, and these passing 

z^£'ysr" ,,! “ '' iM 

.±alsig; 1 g S tilt 1 ” :!■;«;» ■; {*.;!” .i g „„. mi,. „ 

a switch, which also acts ns !i call on thn "r V* tlm ! wn n « ,(m the beH h * 45 

the magnet wliich serves to actimto fl i° n^ n , C c !! lt,uro about tbo bulls is that 
preferably German silver wire in the helix and'ti.us° serveT ru f t,lnce ' min '° 
sumption of battery power. ’ 1 1 prevent a rapid cou- 

aro used? Tho niclhotn ‘ndont* fim'en Wnrkc , 1 ' ( ' 1 ! om ono lmttc ‘ry if tlioso bells .’ill 

substnneo is tlio reduction to tin. I10 »-conducting substaneo witli metallic 

then, to thofumiswhh!hirtaS " f ™" Mr salts by exposing 

of eidoium, or by piaciiic tlin uill.- r In . o a ^ phosphide ol a metal, sueli as phosphide 
Ct II c electroiks nnd'^hdilizfnre'i^ 01 l' 18 ,,n f\ in ■oulod tube provided'will, 
such volatilized metals settle Upland coat tbo°sill^ ° 1 ’“" n8 ° ° r oluctric 8 l m, ' k81 35 

s ”“““ u '»’«>"'i».ti» mMoe 


f A.D. 1877.—N° 2909. 9 

Edison’s Impts. in Controlling by Sound the Transmission of Electric Currents, do. 

instrument may bo mado to control an air valvo of a reservoir in which air is stored 
under a regulated pressuro. Tho air allowed to esenpo will act with great power 
upon a local diaphragm. Tills diaphragm, to obtain clear sounds, requires n damper 
to cheek prolonged vibrations. It must bo damponod by holding tho fingers against 
fi it, or by n tightly stretched cord rubbing against it, or by a screw provided with 
a rubber tip held ngainst it. For repeating from ono circuit into another I uso 
with tlio rocoiving diaphragm the elastic tension regulator Fig. 1 in addition to tho 
clcctro-mngnot, and connect tlio rolay or second circuit through tho same, so that 
waves received from tlio distant station cause tlio magnet to vibrato, tho diaphragm, 
10 and this acting upon tlio tension regulator transmits tho waves into tlio second 
circuit, nnd they aro received at tho other end by an clcctro-magnct and diaphragm. 
In Bomo instances I mnko a record of tho sound by tlio movements of the 
dinphrngm, using for tlmt purpose a strip of paper moved along regularly between 
two rollers, 25, 20, as in Figs. 14 and 15; and tlioro is a smooth thread or fjno 
15 wire of soft metal 00 botween the paper and tlio upper roller 25, and moving 
along witli it Tlio diaphragm 10 of tlio resonant box Is connected by n dolicato 
rod 28 with this thread or wire ns near to tlio bight of the roller ns possible, 
tlioro boing a fork or eye through which tlio thread passes, lienco deflections or 
bends nro mado in tlio thread or wire just before it is imbedded into tlio paper 
20 by tlio pressuro of the rollers; this may bo used to reproduce the sound by 
vibrating a resonant diaphragm by tlio undulations of tho groove mado by tlio 
tlirciul or cord. 

By plncing tho fibrous tension regulator within a small band of india-rubber the 
same is rendered more olnstic, and tlio fiber is allowed to expand by tho bent of 
25 tlio current without altering tlio olectric tension. In cases where a strip of hard 
rubber or a cold of silk or other material coated witli plumbago or metallic foil is 
introduced botween tho diaphragm and a rigid support, tlio expansion and con¬ 
traction duo to tlio passago of tho electric currents will produco a movement upon 
tlie diaphragm corresponding to tlio diaphragm producing tlio electric pulsations. 
30 111 some instances the diaphragm should be freo to vibrato without being cheeked 
by contact witli any stationary substance. I provide for this, by placing upon tlio 
diaphragm or tympan 10, Fig. 17, a smnll cylinder l 1 of hard rubber or non¬ 
conducting material within which is the fibrous tonsion regulator t resting upon a 
pieeo of platiun foil connected to ono pole of tlio battory, and within this cylinder t 7 
35 is a disk l 10 of iron or other metal, loose, but pressed towards the tension regulator 
by a spring t 8 and screw cap l", nnd tho other electric conductor is connected with 
said spring. Tlio inertia of the motal disk causes more or less compression of tlio 
tension regulator as tlm diaphragm is vibrated, and lienco the electric pulsations 
ore sent over tlio line in harmony with tlio vibrations. Nearly the same eifect is 
40 produced by connecting the disk i 10 to a yielding spring t 11 that extends across from 
ono edgo of tho diaphragm to tlio other, ns seen in Fig. 10. This construction of 
tension regulating dovico is especially available with largo diaphragms. In somo 
caseB I uso a sea rubber diaphragm immediately in contact witli the transmitting 
or receiving diaphragm, so ns to check or dampen any prolonged or falso vibration, 
45 nnd render tho sound more clear and freo from prolonged tones. In preparing 
tlio tension regulator I find in somo cases that it is preferable to uso lampblack 
mixed with pure plumbago, amorphous phosphorous, nnd a very small amount of 
non-conducting material, such as rubber dissolved in a solvent that will entirely 
evaporate. 

50 In Fig 10 I liavo represented tho circuit as pnssing through tlio diaphragm 10, 
tension regulator t, nnd a Dulucs dry pile bnttory D, P, B, to tho earth. Tins 
battery is composed of about 300 pairs or paper disks coated with silvor and black 
oxyd of mangnnoso. Fig. 20 illustrates tho device before mentioned for intensifying 
tlio 6ound; 10 is tlio diaphragm vibrntod by tlio sound; 42 is a valvo moved by 
55 sueli diaphragm ; 43 is a reservoir containing air under a given pressure; b is tlio 
diaphragm against which the air, allowed to escapo by tho valvo, acts, and t is tho 
tension regulator to transmit tho electric pulsations, or a hearing resonant caso may 
bo applied at tho somo placo, 


















Edison’s Impls. in Controlling by Sound the Transmission of Electric Currents, tic. 

Many curious ntul useful features liavo boon dovolopod by my oxtonded researches 
in tlio transmission and reproduction of sound. Among these may bo mentioned 
tho fact that a copper diaphragm, or a diaphragm of mica or other flexible material 
containing copper, will net with the core of a polarized electro-magnet in transmitting 
or receiving. If a diaphragm with a metallic button upon it is so close to tlio core 3 
of a permanent magnet, see l''ig. 21, Liiat tlio vibrations of tlie diaphragm by sound 
causo such button to strike tiie core a corresponding electric pulsation will be set up 
m a helix around tile magnet, nnd tlio sumo will act in an electro-magnet at the 
distant instrument by molecular disturbance. 

If tho diaphragm 10 lias a thin tube attached to the center, as seen in Fm «•> 
ami this project into the helix around one pole of magnet 48, the current set upln 
that helix by tlio vibration of tho diaphragm and tube will be nmol, greater than 
that resulting from a Hat armature on tlio diaphragm or tlio diaphragm itself Tho 
iimgnct 48 may be polarized by a helix and a local circuit and battery. If one pole 
of the permanent magnet to", Fig. 28, is connected with the plate e so that the latter u 

polarized by induction, tho current set up in tho helix around one polo of the 
said magnet is intensified. In this case 1 groove the cud of tho helix-pole, nnd 
user ta small piece of sort rubber or tubing that serves to dampen the vibrations of 
the diaphragm, and prevent false or harmonic vibrations in speaking. Fig 24 
represents the diaphragm 10, tension regulator l with its adjusting screw and local 
circuit contammg the battery 13, passing through a primary induction coil 4!), and 

«TOVihmtions i,, f”tT"T 1 t ; 1,!,!trio,, 1 ll y SgoVtc^ 

effect from the line wires, beiii** nditiceiit to ouA* i LOmc ^ ,1L 1, ulucii\o 2 j 

instrument at the distant siatio.fbct^I ^imluctfon coil L'l tlm c^hTaUf 
and use an electro-magnet ill, M, with polarized armature to strike a hell • this will’ 
respond when the key 60 in theloeal circnitat the distant station i o ■■ led .’uu do c 
in 4ig. 25 a similar induction coil 41) mid local i. 1 , , , ' ,, ' 

r;Ss 30 

andMol^t^fol^ <-’• «'« ™ ^ 

distinct. When the diaphragm is arranged Z^nFi'^r, t Umf r‘ m nUd tho sound 
through an intervenimr Bn r! ,f u Da . \ n 20 to acfc upon a spmitf 50, 40 

electric tension by mn^ybg a rai oe of c'l 7* ^ ™ and fall of 

to 50. The greater amiditude (d vibrat nu nf'',? 3 “r t0I1 b' llus adjacent 

bo the electric circuit connections sub i diaphragm the more direct will 

pass along the spring instead of going thrauilnilUhf rSa be0aUS V h \vr id S WiI1 
is an electrophorous or resinous disk fiN , . LS stancu col,s - When there 45 

in Fig. 27, and the line eonncctlot nra f' ,l , t o ol y/« 01 !!S 70!! diaphragm 10, ns 
connections aro made to thesn ,.i no i,.„_i” le 1 , to tllu diaphragm, and tho earth 
to each other in either speaking or hS!“ dl “‘" i 58j U,u diaphragms will respond 
each other, tho wire used forth ."S' " 1 " ,ro several line wires run near 
induction, and false sounds wiU CS “rf" 2 ia influenced by 50 

Placing one or more olcetra-mamiets i 50 Kg 28 inT™° t V 

telegraph, and one or moro olcctro-miu«m.f«rn’-' *| ln . 10 oireuit oi tho speaking 


* .S,wm L "", 1 “*' “,*• ““ *»“ mi .1 50 .l.i 

-nw. 1. ZZZHS&Z&S 


son’s Impls. in Controlling by Sound the Transmission of Electric Currents, tit 

10 currents will bo neutralized, whothor strong or wonk, and will not produci 
falso sounds when tlio speaking tolegrapli is in uso. I also einplny doublo coil 
riro for tlio snmo purposo, one coil being in tlio acoustic wire, and tlio other ii 
wire to bo compensated. 

L convenient fonn for tlio sound recorder or phonograph is to employ a cylindo 
seo Fig. 29, having a liolical groove in its surface covered with tin foil, nnd til 
iiilcr is revolved regularly by clock-work and moved endwiso by a screw on it 
ft, so that tlio indenting point I 1 from tlio diaphragm 10 of h will bo always ii 
with such groove, lionco tlio vibrations oi tlio diaphragm will bo recorded b; 
mting the foil into tlio groove, nnd lionco tlio same sound will be reproduced b; 
point P of the hearing instrument n, giving to tho diaphragm of n the motion 
t result from too indentations or tlio foil moving in contact with such poim 
i f 0 n , m iy be on a flat grooved plate and bo indented and act as before named, 
claim as my Invention,— 

first. In an instrument for transmitting electric impulses by sound, a diapliragr 
yinpnn of mien, substantially as set forth. 

locond Tn an instrument for transmitting electric impulses by sound, tli 
filiation with n diaphragm or tynipiui of an electric tension regulator lb 
ring tlio resistance in a closed circuit, substantially as set forth. 

’bird. The combination in an electric instrunie.it actuated by sound, of 
pliingni nr tyinpan, a conductor, and an electric tension regulator composed c 
liliug mnterinl and electric conducting material. 

fourth. The combination with the diaphragm and electric conductor, of tlio cor 
c nnd tension regulator, substantially as set forth. 

•’iftli. Tn a telegraph operated by sound, tlio transmission and reproduction c 
lummn Voice by increasing and decreasing tlm resistance ol flic circili 
stantially as set forth. 

Sixth. The combination with a diaphragm or tyinpan, of electrolytic foml an 
:treclcs,tlie latter being vibrated by Urn diaphragm and varying tho resistance 1 
electric circuit, substantially as set forth. ^ ^ ^ .. ^ 

•big nii'opeuingor' edge',' against which the consonant sounds act, substantial! 
set forth. ‘ . 

Eighth. In combination with tlio diaphragm or tyinpan and the electric tensin 
ulator, tlio lidjustiug screw or variable pressor to regulate the resistance of tl: 
sion regulator in the electric circuit, substantially as set forth. 

Sinth. Tlio combination with a diaphragm m a speaking telegraph instrument ( 
loving surface, and a recording mechanism actuated by tlio diaphragm or tympai 
istiintially ns set forth. _ . 

i'entli. Tlio combination with ft receiving diaphragm or tympnn 111 a tologrnp 
irated by sound, of a moving surface, a point, and a connection fio,.i the same I 
diaphragm, substantially ns sot forth. 

Eleventh. Tlio combination in an instrument for receiving sounds electrically, 1 
electro-ningiiot nnd arnmturo plate, substantially as set forth. 

I'welftli. The combination in the tclograpliic circuit of two or moro tympana, 
onimt box, mid 0110 or moro circuit closers to each tympnn, subotni.t..dly ns si 
Hi. . 

ITiirtenntli. Tlio combination with tlio diaphragm of a resonant case, of circu 
mections at botli sides of tlio diaphragm and a battery, substantially as show 

Fig. 10. 

Fourteenth. In n telegraph instrument operated by sound, a resonant box 1 
v, a diaphragm and Hcxiblo circuit connections, substantially as set fort 
loroby tlio instrument is made portable and can bo placed to the mouth 
inking. 

Fifteenth. In a telegraphic instrument operated by sound, an olectro-mngnet m 
onimt plato or diaphragm provided with a handle and iloxiblo conductoi 












12 A.D. 1877.—N° 2909. 

Edison’s Tmpta. in Controlling by Sound the Transmission of Electric Currents. <£o. 

Sixteenth. The receiving instrument consisting of an olcctro-magnot, a enso and 
a loose motallio plate, arranged and opornted substantially as sot forth, to act as a 
call or to receive tho message. 

Seventeenth. In a telegraphic apparatus oporatod by sound, ono or moro contact 
points of yielding material that produco a rise and fall of tonsion proportioned to 5 
tho pressure exerted by tho diaphragm, substantially as set forth. 

Eighteenth. In a telegraphic apparatus operated by sound, a receiving instrument 
provided with a resonant surfiico.in combination with a frictionnl surfaco movod bv 
power and acting in connection with tho olectrio current to vibrato such resonant 
=i^rs^: leSCOrrOSP ° ndinS t0 tL0S ° at th ° transmitting apparatus, 10 

Nineteenth. The combination with a thormo-olectric pilo of a vulcanito or Wl 
rubber diaphragm, substantially as set forth. 

szs- *• “• 

T1 ‘° °? Inbi . ntttion ,'vith tho diaphragm and tonsion regulator of a 
i“ f“g “2 8U0 aDd “ ir °“ P at ° Up0 “ th ® dia P hra S n) . m sot forth and shown 

-“4ssr^.”ssft aaa-is 

JvWSSSAnJS”“>*»“-J-“iving 0 rft. » 

and a inagiiol'’ ana’ Z^of’wMch d 1 “ st ™ nlcnt ' of o11 iron diaphragm 

specified. ” attaclied to the magnet, substantially us 

a diap,iragm ° f 35 

cirenW nty in'aStmutan'd‘a edl indU ° ti ° n 1 d ’ n ^> *» d 
substantially as sot forth. * a Cfl ^ 01 soun d cr at the distant station, 

or ,k,a„al, In „ 

to ss5srsr*^ p»sp««« 

reproducing sound,"ono”or^M^el^ro'mn^ote^d Contninin S in stniments for 

sesssr* u » .. 

Imnd'lndTeaT e thi S Twenty 'buHhly rf SSS.’ S° 1“° "* ^ j 
Witnesses, THOMAS ALVA EDISON (ls) 

L0ND0!fi 

















































r 



A.D. 1877 .N° 2909*. 


Controlling by Sound the Transmission of Electric Currents and 
the Reproduction of Corresponding Sounds at a Distance. 


THE EDISON TELEPHONE COMPANY'S DISCLAIMER AND 
MEMORANDUM OF ALTERATION. 

[Edison’s Patent.] 

Filed 10th February 1880. 

TO ALL TO WHOM THESE PRESENTS SHALL COME, wo, tho Edison 
Telephone Company of London, Limited, of 11, Queen Victoria. Street, in tho 
City of London, aond greoting:— 

WHEREAS Her Moat Excellent Majeaty, Queen Victoria, by Her Royal Letters 
5 Patent, under tho Great Seal of Great Britain and Ireland, bearing date at 
Westminster, tho Thirtieth day of July, in the Year of Our Lord, Ouo thousand 
eight hundred and seventy sovon, in tho Forty-first year of Her Reign, did for 
Hersolf, Her heirs and successors, give and grant unto Thomas Alva Edison ot 
Menlo Park, in tho State of Now Jersey, United States of America, his executors, 
10 administrators, or assigns, or such others nB ho his oxccutors, administrators, or 
assigns should at any time agreo with, and no others, from time to time and at all 
times thereafter during the torm thorein expressed, should and lawfully might 
make, use, exeroiso, and vend within tho United Kingdom of Great Britain and 
Ireland, tho Channel Islands, and Islo of Man, an Invention of Improvements l in 
la Instruments for Controlling by Sound the TitANpussiON of Electric 
Currents and the Reproduction of Corresponding Sounds at a distance, 
for and during tho term of Fourteen years tlionco next ensuing: An “ J'', ” 
Pursuance and performance of a proviso in the said Letters Patent contamed the 
said Thomas Alva Edison did within Six cnlendar months next after tho date of 
20 the said Letters Patent cause a Specification in writing undor his hand aud seal 
purporting to particularly describe tho nature of the said Invention, nnd in what 
maimer the same was to bo performed, to bo duly filed in the Great Sea Patent 
Oflice: And whereas by Indenture bearing date the Second day of August, One 
2R A , , 0US “ Dd oi 8 llt hundred nnd soventy nine, and mado between tho said Thomas 
25 fjva Edison of the one part, nnd m tho Edison Telephone Company of London, 
Limited, of the other part, tho said Thomas Alva Edison assigned unto us tho said 
Edison Telephone Company of London, Limited (inter aim), tho said hereinbefore 
recited Letters Patent, and all rights, powers, authorities, privileges, advantages, 
[Price Gel.] 


































2 A.D. 1877.—N° 2909*. 

Edison's Impia■ in Controlli ng by Sound the Transmission of Electric Currents, £c. 

profits, emoluments, and bonolits to tliu said Letters Patent, appertaining or 
belonging: And whereas since tho date of tlie snid Assignment wo have boon 
advised and have ascertained that tho said Specification contains matters which are 
of doubtful novelty, or which aro not of sufficient practical value and utility to 
justify tlioir retention ; and we aro therefore desirous of striking out tho wliolo of 5 
tho claiming clauses contained in tho said Specification, with tho exception of the 
first, second, eighteenth and twentieth claiming clauses, and of striking out pnrts of 
tho description contained in tho body of tho said Specification ; and also of otherwise 
altering tho said Specification, and correcting certain clerical errors contained in tho 
said Specification in manner more fully hereafter appearing. 10 

NOW KNOW YE, that we tho said Edison Telephono Company of London 
Limited, by and with tho leavo of Her Majesty’s Attorney General, and for the reasons 
aforesaid do alter tho said Specification, by striking out of the said Specification 
printed by tho Queen’s Priuters, and published at the Great Seal Patent Office in 
One thousand eight hundred and seventy nine, the words “ tho saino ’’ which 15 
occur on pngo 4, at tho end of lino nine, and tho beginning of line 10 respectively, 
and substituting therefor tho words " a corresponding "; we also striko out tho 
word “tho" which occurs between tho words “and” and “electro” on tho said 
pngo, lino twenty two, and substitute therefor tlie word “ an"; wo also insert 
between tho words “ tho” and “ instruments" which occur on tho said page lino 20 
twenty five the word “ transmitting ” and we striko out tho letter “ s ” at tlie end 
of the said word “ instruments ” ; wo also striko out tho word “ aro ” which occurs 
on tlie same lino and substitute therefor the word “ is ” ; Wo also insert botween 
tho words “in” and “Pigs.” (ail abbreviation of the word Figures) which occur on 
tho same lino, tho words “section in” and wo strike out the letter “s” in tho snid 25 
word “Figs”; we also strike out tho words commencing with “ and ” on the said 
lino twenty five and ending with the first word “ instrument ” on lino 20 of tho 
snid pago four we also strike out tho words " of tho ” which occur between tho 
Figure “2 ” and tlio word “receiving” on tho snid lino twenty six and substitute 
therefor the words “ represents a ”; wo also add after tho word “ instrument ’’ at 30 
the end of tlio said line twenty six tho words “ which may bo employed with it” ; 
we also striko out tho word “ tho ” at tho commencement of lino twenty seven ou 
tho said page four and substitute therefor the words “ referring to Figure 1 tho "; 
wo also strike out that portion of tho Specification commencing with the words 
“in Fig" on page 5, lino forty one, and ending with the word “ sound ’’ on pago C, 35 
lino three; we also striko out that portion of tho Specification commencing with 
the words “I also ” at the end of lino eight and ending with tho words " the lino ’’ 
on lino eleven of the said page C ; we also striko out tho wliolo of lines twenty four 
to twenty eight inclusive on the said page G ; wo also striko out tho words “ to 
record which aro repeated on line thirty five of tho said page G mid ndd tho lettor 10 
s to tho word “ rest ” which occurs on lino forty seven of tho said pago G. 

Wo also strike out of page 8, lines thirty seven to forty two inclusive, and lines 
forty six to fifty three inclusive. Wo also strike out of pngo 9 lines eighteen to 
twonty three inclusive, and lines thirty sovon to forty ono inclusive. Wo also 
siriKo out ol pago 10 hues seventeen to thirty seven inclusive. Wo nlso striko out 15 
pngo 11 lines ten to thirteon inclusive, and lines forty four to fifty seven 
inclusive, and wo add at tho end of lino thirty seven of tlio said pngo eleven after 
wwrtnnmeil tlio words followingI would obsorvo in conclusion that I 
0aln } generally tho transmission and reproduction of sounds by increasing 

Md decreasing the resistance of the circuit, nor do I claim separately any of the 50 

L,ri n J,K described and illustrated in tlio accompanying 

WO 0.1(1 tlio Idler " a ’• to tlio word'' 1 ” nn !l “ Him « ol tlio rnilil linso 11 . on* 

Ulo jold word " regulators " woIntoruSo worila " LullaUmtirUly'naVicnSnb’ fo’a Ss'criSd S 1 re,ul "^Buli'tom," and alter 

finesTnf in°?l C?I l t “ h 1 ere . inal }?r mentioned, but a.”' °"We also strike out of pago 12 

to fiftv six inXL’r'T 0 ’, 1 ' 110 -! W 8i V nd thirt y forty two 

xi y , • We also Btnko out the word “ eighteenth” which occurs at 

the commencement of line thirty one on the said page 12, and substitute therefor 56 


plwlalmer Ac. ■ A.D. 1877.—N° 2909*. 8 

SS. in Controlling by Sound the Transmi ssion of Electric Currents, < to. 

». wool • tun;; w. *> & 

5 out of jingo Id lines one to lourtee hereunto a copy of tho said 

SjiSSTS Ri.Urr.wXn L n—W, tl,0 wnmu. >-"« *«” 

being omitted. of electrical instrumenU in which sound 

ariX^iTSi^ *** d “ ne " i, “ “ 

6ta M°,sieal tones may also be sent, but my present Invention is especially available 
15 in transmitting and roceiving'7,j'°;'™Xe notes each have a definite period for 

e.£rSK^ -S Mrs 

‘"In,,..... Invention I ->■« - •' M 7*5*3 

as to reproduce the articulation b.v ncb“g “P 0, ‘ " rc| ^ osc iit C d in section in 

,(7 17 ,'..t‘ L - ‘ 

with it. ,,ti n f a size mid shape adapted to 

30 Inferring io f&X «•* ‘ £ e *d or sid e and a diaphragm 

articulation at tho transmitting station. . Invontion but in developing 

« “ d *“ ta “ “ d "’ 

flexible conductors to the battery and lmo iesi J> ,, t pluC o Hie hearing 
mid brought to the mouth, and ... like man no t is ^ w i.l. the plate o 

iiislriimoiit Fig. 2 in a movable haiidlo b , bo that I 0 f bearing, and tho 

lignins! the car; this brings the sound close to .. SO unil xvml prevents 

resonant plate touching tho ear increases the d.st.nctness ol the sound 1 
any false or prolonged vibrations of tlio plate. ... instrument as a fixture, 

In some of tho modifications I have Bhown tho sp abmg «m.mo 
»0 and also tho hearing instrument ns a fixed resonant tube, tlieso „ 

suit the persons or tho places. Walton is the peculiarity of 

Tho first especial feature that requires sopn . ,lifli c ulty in reproducing • 

I the resonant tube for tho voice. 1 have experienced g.eat difhcl^ .nj ^ 

.. Ihc sound of the hissing consonants, such as #. moull| nn d does not act 

that this sound is doilcctcd downwardly in b resonant tube below 

distinctly upon the diaphragm. By providing an od£^d tb 0 ‘Xations are given 
| tho mouth upon which such consonant bounds aio i 





















4 A.D. 1877.—N° 2900*. 

Edison's Impta. in Controlling by Sou nd the Transmission of Electric Currents, Ac. 

either to tlio resonnnt tube or deflected to the dinpliragm, I find it preferable to 
employ a hole c at tlio lower part of the mouth pieco agninst the edges of which the 
downward sound waves aro directed. Tho Baino ofiect will bo produced by a 
vibrating edge placed in tho lower part of tho mouth picco, or tlio oponing into tlio 
resonnnt box may bo contracted to about half an inch in diameter to effect the sanio 5 
purpose. Tho next feature requiring consideration is the character of the diaphragm 
in the speaking instrument. 

Many materials have been employed by mo such as metals, horn, vellum, celluloid, 
ivory, &c., but almost all of theso produce a prolonged or secondary vibration from 
their own resonnnt character, hcnco tho articulation is defective and tho sound H 
vibrations blend. 

After extensive experiments I find that mica is almost entirely froo from any 
resonant action, and hence it will respond with tlio greatest accuracy to tlio sound 
vibrations, and being of a laminated character can bo employed of any desired 
thickness, and when secured at its edges responds witli tlio greatest accuracy to tho b 
sound vibrations and does not require to be strained; furthermore, the changes of 
tempemturo and atmospheric condition liavo little or no effect upon tho mica 
diaphragm or tympan. 

I find that it is not practical to open and close tho lino circuits in instruments 
for transmitting tho human voice, tho circuit to the lino must bo always closed and 21 
tlie transmission bo produced by a rise and fall of electric tension resulting from 
moro or less resistance in tho line. This rosistanco may be produced in sovcral 
ways. I have shown several which will hereafter bo nnmed, but I find tho most 
delicate to be small bunches or tufts or disks of semi-conducting clastic fiber, such 
as particles of silk and an intermediate conducting or semi-conducting mntorial; 2i 
this device I call an electric tension regulator, it is more or loss compressed 
according to the vibrations of the diaphragm or tympan, and the olectric current 
rises in tension as it is compressed or lessens as tho liber expands. This fiber is 
placed in a small roll t between the delicate diuphragm spring u, Fig. !), and the 
variablo presser v adjustable by screw or otherwise in tlio electric circuit at this 31 
point, or it may be within a cavity in said presser v, as in Fig. 1, tliero being a 
delicate cork center pieco w to tho diaphragm b, with a piece of platina foil x in 
contact with the fiber; in all instances tlio telegraphic circuit at the diaphragm is 
mado by a thin strip of platina or similar material, extending to the center from 
tho lmo or battery connection. -T 

the fiber is rendered somi-conductivo by being rubbed with plumbago, soft metal, 
or similar materinl, or by a deposit of metul upon its surface, or by fino particles of 
conducting or semi-conducting material mixed with it, the conducting power 
varying with the density of the tuft, or bunch of fiber. 

J hc deliente spring it, Fig. 9, upon tho mica diaphragm 6 is easily secured by 41 
solder passing into fino holes bored in tho mien. 

. sonic cases I make use of a variablo resistance resulting from greater or less 
intimacy ot surface contact sucli as would result ftomadisk covered with plumbago 
placed adjacent to a diaphragm also covorod with plumbago or other seini-conducting 
miterial so that the proxuuity or extent of surface contact will produce l'iso and 4' 

"f tonsion, tlio respective parts being in tho telegraphic circuit. I sometimes 
perforate the diaphragm 10, Fig. 18, ami place a strip of olastic materinl 40 across 
rn If-i“ P il Sram OVOr , lh ?, hol .°- and u P° n this a picco of foil, so that tho samo 
are n™vi!w^ r01 ^ , \ 1 ' ,ratl01u, i aml in somo instances two or more diaphragms 

ti 'v different sides of tlio resonant box, each with its own tension 51 
tensing 'Ji ' 0 dmpliragms boing either tho samo or of different sizes, characters, or 
tendon ,. S0 w t0 , re . s P on d to vorying sounds or acoustic condition, tlio various 
tension rag,daters being all in tl.e electric circuit, this will produce greater rise and 
tnneouslv on t / 01 1 ° n ®° 1 ' lne3 , ln COIlse quonco of the diaphragms acting simul- 
«~tblooof t r i ° a r ?8nlntors. In some instances it is preferable to make 5 
all too eo 'ia ? v ^• t 10 s P cakl “S instrument sufficiently large or flaring to receive 
all tho sound vibrations, whether coining from tho mouth, nose nr throat. The 


. A.D. 1877.— 29,09* ■ ___ 5 

^ir^numt 0 to^roprothicof\lio 0 HOund > tupon a delicate diaphragm by giving to tho 
10 rame a vibration similar to that ori ?|" nU ^^ V d e ^ ip |fra"mh’avi’ng a knife-edge point; 
h, Fig. 4, is the indenting tmn^ttor, U.e ^ - ^ * jaUo v 

i iB the paper which lias proj J diaiiliragm of h when tho drum is in motion 
shaped rib 0. The movement of the dmpli^g ^ ^ ^ varying depths according 
causes tho kmfo-odgo point J ta 1 , 0 . a „ m thus those indentations represent 

15 to tho amplitude of vibration of the djapbragm, , mmim voico . The paper, 

accurately all the tones and d thSmch a second apparatus n, Fig. 5, almost similar 
after being indented, is passed tbrougha^ ^ W tho rniae d indented rib b, the 

'its bemgconneeteil U,» iKpriSs J"£ moiSS *o“t iirfonlta 
name motion to tho diaphragm of n ,» , P i. y ie diaphragm 10, Beo Fig 6, is 

sounds are to be transmitted over a‘ t before described, to 

provided with a cork disk w and fib ous teos'O ^ ^ Tho 80un d may bo 

25 produce the rise and fall of cfe°tno tonal» of opora tcs a very 

recorded in ink, as represented m 1-ig. 7. o « 1 ^ b(j wido or narr ow 

flexible self feeding pen o, and causes tl diaphragm. The ink used should 

according to tho amplitude of v ‘ krall0n of t all ' y time thereafter through the 
dry quickly and the strips may bo passed ■at g J po i„t or points resting 

30 instrument shown in Fig. 8 beneath esonant diapliragm, and tho ink marks 

on the paper, this arm is connected.with ui esonan^ ^ dopo3ltod , 

produce moro or loss friction accordmg to t b d e the vibrations of tho 

and this will set the diaphragm of n vibrating a v 

diaphragm of h. . .. , , _ oafc tho paper with a substance which 

35 An obvious modification would bo ^ un P 8 *,Ll paper might be used and 

iAwtooltu. 

40 in tho receiving diaphragm. connec tion with the transmitting instrument, 

1 sometimes arrange tho battery iu w 

os shown in Fig. 10. , f v ♦ u j 9 tho diaphragm 10, and at each 

h is tho resonant chamber at the end of w po ints mado of compressed 

side of this diaphragm there arc springs c, » ® substance not liable to rapid 

45 plumbago mixJd preferably with anysu^ ^ be d 

decomposition or tho elastic or fibro t diaphragm, and make contact 

Theso points fnco each other on oppoBito sides of lb- 

with platina foil disks secured to the «P 8 ■ , j n tbo a ;d 0 0 f tho chamber h ; 
The spring c a passes through a hole m t tlio lino or spring c*, and 

60 a*, nra the main batteries T When tho springs efV- and c 3 aro 

the battery <l 3 has copper to tho line or p S ,, no uurren t passos to tlio line, 

adjusted to make contact with tho dinphra fl y Bid say c 1 , causes a 

but when the diaphragm is vibrated nMvenwj ^ ^ lessening ? f the 
greater pressure upon tho plumbago o 1 ® f tho batteries c l and 

65 pressure on the plumbago on c\ a negative current to 

Uno Vl unnn ^'return of^tho will again 















Edison's Impts. in Controlling by Sound the Transmission of Electric Currents, <Sn>, 

neutralize each other. The vibration of tho diaphragm to tho other sido causes tho 
nressuro to bo reversed, and tho battory <P will solid a positivo current to the lino. 

As the tension regulator of fiber or of plumbago docrcasos and increases its 
resistance enormously under slight changes of pressure, it follows that tho strength 
of tho electric waves will bo in proportion as tho speukera voice is strong or weak. 5 
In Fig. 11 is shown the contact spring, which may bo used adjacent to tho 
diaphragm at one or both sides thereof, e 3 is a U shaped spring secured to tho 
screw o' which is adjusted back and forth by tho thumb nut e 5 ; c“ is tho pillar 
holding*such scrow; r is a piece of soft rubber or equivalent substaneo placed 
botween tho prongs of tho spring e 3 ; c 7 is a wire or bnnd which serves to bind tho It 
prongs tightly against the rubber r so as to prevent tho prongs noting ns a tuning 
fork and transmitting harmonic vibrations not desirable ; r 2 is tho plumbago contact 
point. Tho object of the V spring and rubber is to present a semi-rigid point for 
contact so as to prevent a rebound and allow of a slight yield when tho plumbago 
is pressed by the diaphragm. In Fig. 3 the diaphragm of the receiving instrument 1! 
is vibrated by a strip of paper chemically prepared that is in motion, tho pulsations 
of electricity passing over the lino and producing more or less friction botweou tho 
pnper and an arm upon tho diaphragm. 

Tho resonant box or chamber n is provided with a diaphragm as aforesaid, and 
to said diaphragm an arm ft 2 is connected. At its outer end is an adjusting scrow It? 2( 
that presses upon a platina faced spring ft 4 that is secured to this arm, and said 
spring rests upon tho strip of paper that passes over tho drum ft'. 

The pnper is moved slowly by rotating tho drum ft', and the waves of electricity 
coming over tho lino pass through tho arm ft 2 to tho platma-faced spring ft*, tlionco 
through tho paper to tho earth. 21 

If a negative current passes in the opposite direction nearly all friction betweon 
the platina plate and the paper ceases, and tho diaphragm of tho resonant box n 
retains its normal position. 

When the positivo current passes through the samo channel tho normal friction 
of tho paper is augmented, and tho chemical surface acting upon tho platina spring 3( 
arm serves to givo a forward movement to tho diaphragm of tho resonant box. 

Thus the mechanical force applied to move the chemical paper or surface acts 
with tho electric current to produco tho vibration of tho diaphragm of the resonant 
chamber, and tlieso vibrations will correspond to those of tho diaphragm b made by 
speaking in tho tubo a. 3! 

The principle of this mothod of obtaining motion by electro-chemical decomposi¬ 
tion is, that when a moving surface is in contact with a slightly yielding substaneo 
tho tendency is to move tho latter by and with tho former. If tho circumstances 
of contact aro varied tho adhesion of tho surfaces will be sufficient to cause tho 
moving surfaco to movo tho yielding substance or elso to cause tho yielding surface 4i 
to slip moro freely, and by its spring go in the opposito direction to the moving 
surfaco. 

Tho passage of electricity at the surfaces in contact will change tho frictional 
ndhesion, making it moro or less according to tho substances employed. By 
balancing the mechanical forces so that when tho surfaces in contact are not 4 
electrified tho moving surfaco carries with it tho yielding surface, and when 
electrified the yiojding surfaco slips back, over tho moving surface a mechanical 
movement is obtained that is dependent on tho electrical condition of tho Burfacos 
in contact. 

When it is requisite to obtain very perfect articulation, and when loudness is 5 
not essential, I adopt a modification shown in Fig. 12 of the device for compressing 
and expanding tho tuft of conducting fiber, which modification consists in placing 
between tho diaphragm 10 and tho fiber t a vibrating tonguo 21 of Btcol, perma¬ 
nently magnetized, and arranging it to act in tho snmo manner upon tho tonsion 
regulator t as if it was the diaphragm. I replace tho cork upon tho diaphragm by 5 
a thim armature of iron 22, which is in close proximity to tho magnetized tongue, 
which tongue is secured ,at one end .like an acoustic reed. In this position the 


AJ>. 1877.—N° 290 9*. _ ]_ 

diaphragm is ft«» to■' 
KgTis made ?o S pcrform what the diaphragm previously performed in varying 
tho tension of the clcetricity on 11 o ino. ^ C( ig e9 when placed in the speaking 
5 A plate supported cceontnwUy and f t. eg * Tho civcu j t with this 

tube responds advantagoouBly toJtUo^toncs^ pW arou „ d ita edges, 

nlato is completed through ono o _ • inilnlifinifl ftimaratus signal bolls so 
In practico I combino with tho spea l . n 8 tho^ino is thrown upon tho boll by 
arranged that when the telephone is "otm use tno 
10 a switch, which also acts ^“■callont ^ SO rves to not „ato the bells 

Ono feature about tho bells is that tuo ma Gorman silver wire in tho helix, 

is made of very high resistance, using preferably G A largo number 

and thus servo to prevent a rapidbells aro used. The 
of tclophonic wires may bo wor ]“ d * . Jgabstonco with metallic substance is the 
15 method I adopt for coating non ‘““ d “ , l thc ; r sa lts by exposing them to the 

20 metals settlo upon and coat tho silk. factories, the tympan of tho receiving 

When great loudness is ^oVan ^- va vo of a reservoir in which air is stored 
instrument may bo mndo to contiol an an vaivo wl| , 

under a regulated pressure. Tho air allowed ^ H0U nds requires a damper 

upon a local diaphragm. Tins diaphragm holding the fingers against 

25 to check prolonged vibrations. It must bo P screw provided with a 

it, or by a tightly stretched cord rubbing against it, oi uy 

rubber tip held against it. . j hy the movements of the 

In soino instances I make a record o moved along regularly between 

diaphragm, using for that purpose a strip ol pape thread or fine wire 

30 two rollers 23, 20, as in Figs. 14 and la, and there m ^ n)o „g with 

of soft metal 30 between tho paper and t>'O u Ppc.roU . # rod 28 with 

it. The diaphragm 10 of the ~ut box s con ^ there being a fork 

this thread or wire as near to the b.glit of the loiio^^^^ ^ b(mdg ^ ]nft j 0 „ 
or eye through which the thread pnssea, tlie papor 'by tho pressure of the 

35 the thread or wire just before it 19 embedded yilrmting a resonant diaphragm 

rollers. This may bo used to reproduce the Mmid by vm a^^ 

by tho undulations of tlio groove made by the tnrea ban( j of Ind ia rubber 

thKK l ° ° Xpand * ^ 1 

40 of the current without altering the eleeiric tension without being checked 

by a spring t 8 and screw cap and tho oilier 

the said spring. . , nv t 0SM compression of tlio tension 

Tho inertia of the metal disk causes i ' c j cctr i 0 pulsations aro sent 

50 regulator ns tlio diaphragm is vibrated and , t sam0 effect is produced 

over tho line in harmony with tho vibratm ( u,that extends across from one edge 

by connecting tho disk f 10 to a yielding spri g qq lis construction of tonsion 

i of the diaphragm to the other as seen i ... ?*diaphragms* . , . 

j regulating device is especially n-vni’abIc w ^ 8 immodiaUly in coulool withthe 

o5 la some cases I uso a soft rubbu diaph b . dam pon any prolonged or 
transmitting or receiving diaphragm so as to cUcok i 




















8 . A.D. 1877.—2909*. 

Edison's Impts. in Controlling by Sound the Transmission of Elcclrio Currents, iic, 


false vibration and rendor the sound me 
In preparing tho tonsion regulator I find 
lampblack mixed with pure plumbago, ar 


•c clear and fi'eo from prolonged tones, 
in some cases that it is preforablo to uso 
lorphous phosphorous, and a vory small 


amount of nonconducting material such as rubber dissolved in a solvent that will 
entirely evaporate. _ 5 

In Fig. 1!) I have represented tho circuit ns passing through tho diaphragm 10, 
tonsion regulator t, and a Duluc’s dry pile battery D, P, B, to tho earth. This 
battery is composed of about 300 pairs of paper disks coated witli silver and 
black oxyd of manganese. 

Fig. 20 illustrates the device before mentioned for intensifying tho sound ; 10 is 1 
tho diaphragm vibrated by tho sound j 42 is a valve moved by such diaphragm; 43 is a 
reservoir containing air under a given pressuro ; b is tho diaphragm against which 
the air allowed to escapo by tho valve acts, and t is tho tension regulator to transmit 
tho electric pulsations, or a hearing resonant case may bo applied at tho same place. 

Fig. 24 represents the dinphragin 10, tension regulator ( witli its adjusting screw I 
and local circuit containing tho buttery B passing through a primary induction 
coil 4!), and there is a key 50 in the samo circuit. A secondary induction coil 51 
is in the lino circuit and is miiuenccd electrically by tho change of tension in tho 
local circuit by tho vibrations of the diaphragm 10. Tho secondary coil is some¬ 
times required with many layers of fine wire to set up a current of high tonsion to 2 
overcome the inductivo effect from tho lino wires ; being adjacent to each other I 
place tho receiving instrument at the distant stntion between the induction coil 
and the earth as at It, and use an electro-magnet E. M, with polarized nnnaturo 
to strike a bell; this will respond when tho key 50 in the local circuit at the distant 
station is opened and closed. *_> 

In Fig. 25 a similar induction coil 49 and local circuit is represented, but the 
tension regulator is made of platinu foil upon tho surface of two soft rubber tubes, 
one on the diaphragm, tho other on the adjusting screw. A shunt and rheostat 
at It serves to prolong tho magnetism in tho induction coil, and thus ensure a 
gradual rise and fall of electric tension in tho lino instead of a cessation of tho samo 31 
when the plntinn surfaces separate, and at tho receiving diaphragm c the rise and 
fall of electric tension in tho line and its helix acts upon tho permanent ma f, net to 
produco the vibrations of the diaphragm c, and by connecting a shunt around tho 
helix, and placing therein the secondary battery S, B, composed of metallic plates 
m acidulated water, the action is rendered more uniform and tho sound distinct. 3 

When the diaphragm is arranged as in Fig. 28 to act upon a spring 50 through ' 
an intervening piece of soft rubber, said spring 50 produces riso and full of electric 
tension by employing a rango of resistances 57 with spring tongues adjacent to 50. 
the greater amplitude of vibration of tho diaphragm the moro direct will be tho 
electric circuit connections, and tho less resistance, because tho circuit will pass 41 
along the spring instead of going through all the resistance coils, 
s', C n 6C , „ 1 J no r f rlm ? a <* other the wire used for the acoustic or 
l P cmmtLpl H,™ P r l ,nfl ri d >y Inductl0 "- ftlld fll,se souiula will ho produced, 
the cbm, r Of ? ^ by ? la0,ng 0no or ,noro olectro.mngncts 59, Fig. 28, in 

circuit of 1 thl lr f ,kln . g teIu 8 ra phi and ono or moro electro magnets 00 in tho ..41 
c roint of the adjacent wires, and bringing the opposite cores of 00 at such a 

induction^In tl a r° ^ ft . oert 1 ail ! "'ignotic action will bo set up in 59 by 

or lines ' * °PP° slt0 direction to tho induction currents from tho adjacent lino 


no? J in use 4 unt tl mi " bat "' oen tllesn , 'fftgnols when tho speaking telegraph is 5 
currents hen ic ,S , S(,und at tho diapl.rng.i, 'from tho induction 

not wmlntc n 0U11 ' 0nt 1 s "'I 11 bo neutralized whether strong or weak, and will 
double coils Whe " tho 3 P° akin S ‘e'egraph is in use. I also employ 

6lfsce 0 Kg.2? 4 liavrn^ >■ to employ a cylinder 

g J, Having a Helical groove in its surfaco covered with tin foil, and tho 


BW.lm.r4e. A.D. 1877.—N° 2909*. 9 

^r^MTi n Controlling by Sou nd the Tmmmssi^J^olr^urr^^. 

1,0 The foil may be on a Hat grooved plate, and be indented and act as before 

named. , . . . T no( . c i a -. m rronorally tho transmission and 

10 I would observe in conclusion that I do re y ; s tanco of the circuit 

reproduction of Bounds by inoloas , = or arrnngomonts hereinbefore described 

15 1 ^"inTn^tramcnt for transmitting electric impulses by sound, a diaphragm 
or tympan of mica substantially ns sot forth. . , by sound, tho com- 

Second. In an Instrument lor transmitting electric ia £ a n l3 liBllJ . £ 1 , on ,| 11 i K ,i„ r o ,ic.crii«4 
.. ... or tvmnan of an electric tension regulators a for 

varying" tho'rcsislmco in a°closed circuit 8^ f ^ b ' ving instrument 
20 Third. In a telegraphic surface, moved 

provided with a resonant sui face ll electric current to vibrato such 

produco°tone3 Responding to those at tho transmitting 

substantially as sot forth. ot Lomion, 

In witness whereof, tho said ^ d,3 ° n h b ^^ lb °'' an ? 0 e a Pa the Twelfth day of 
30 caused their common seal Ito bo he em toaluxe.i, 

November, Ono thousand eight hundred and seventy n . 

@ E P. BOUVERIE, Chairman. 

G. K GOURAND, Director. 
ARNOLD WHITE, Secretary. 

35 To the Commission ers of Patents for Inventions. 

I hcroby grant my fiat, giving leave to thojjf^"Lettcrs^Patfl'nt, to Ulo in 
Company, of London, Limited, the nssignees of Bnm0 relates, tho 

" ssrWaSr.fa ?ti y.‘» -«»«*>■» j, “ a 

"£&» „F numb.ra, »d "»<« * 

Declaration. John Holker, 

45 „ „ , , Q an Attorney-General. 

Dated this 9th day of Fobruory 1880. 

L03D0Si I’rmw.1 by Omm i» Ke™' 

'por tier Majesty'll Stationery Office. 















N° 2909". 


Controlling by Sound the Transmission of Eleotrio Currents and 
the Reproduction of Corresponding Sounds at a Distance. 


THE UNITED TELEPHONE COMPANY’S DISCLAIMER AND 

MEMORANDUM OF ALTERATION. * , 

[Edison’s Patent.] 

Filed 13tli Juno 1881. 

TO ALL TO WHOM THESE PRESENTS SHALL OOM| ^ 

United Telephone Company Limited, ocml greeting. WHEREAS G J; 
Excellent Majesty Queen Victoria, by Her Royal , h T) ; t ; tll j ay 

Seal of Great Britain and Ireland, bearing date at Weslmmster the Ihirtian uay 
5 of July, in the year of our Lord One thousand eight l^d and Bove.ay seven, 
in the forty first year of Her reign, did, for Herself, State of Now 

give and grant unto Thomas Alva Edison, of Men ° ft*“ *"*^1 Her 
Jersey, United States of America, his executors ^“‘“J^hT'lho satdViomas 
special license, full power, solo privilege and authority, > j e ]jj 3 

10 Alva Edison, his executor, administratore, or assigns, <>r such others ns he ms 
executors, administrators, or assigns should at.any'*3^^ 
from time to time and at all times during the term there P , f q fc 
lawfully might make, use, exercise, and vend, w.thm the Un.WK.ngd^m of Giea^ 
Britain and Ireland, the Channel Islands, nnd q OBND TnE Transmission 
15 "Improvements in Instruments for Controllingi by: Sound '•nUTUgam AT 
of Electric Currents and the Reproduction of Oram™®™™ensuing: 

A Distance,” for and during tho term of f ““ rtccn jJ in t |m 8 aul Lottors Patent 

And whereas in pursunneo and porformanco of a prov w 1(mdftr mont ]j g noxt 

contained, tho said Thomas Alva Edison, did, wtbin writing undor his 

0 after tlie date of tho said Letters Patent, causo a Spec sniif Invention, 

hand and seal, purporting to particularly describe tho na Great 

urtjttusas su, 

fhe said horeinbeforo recitod Letters Patent, and all rig , p » 


[Price Cd.] 
































2 A.D. 1877.—N° 2909**. vwm ™,.*, 

Edison's Imple. in Controll ing by Sound the Transmission of Electric Currents, At, 

privileges, advantages, profits, emoluments, and honofits to tlio said Lottors 
Patent appertaining or belonging: And whereas on tho Thirteenth Novombor, 
Ono thousand eight hundred and seventy nino, tho said Edison Tolophono 
Company of London, Limited, petitioned tho Commissioners of Patents for leave 
to amend cortain parts of the said Specification of tho said Lottors Pntont, which 5 
petition was inferred to Tier Majesty’s late Attorney Gonoral, Sir John Holkor, and 
loavo was given to tiio said Edison Telephono Company of London, Limited,, to file 
in the Great Seal Patent Oftico a Disclaimer and Memorandum of Alteration, as 
appears by the fiat of the said Sir John Holker, dated tho Ninth day of February, 
Ono thousand eight hundred and eighty, and the said Disclaimer was duly filed in 10 
the Great Seal Patent Offico on tho Tenth day of Fobruary, Ono thousand eight 
hundred and eighty: And whereas by indenture bearing date the Twelfth day of 
July, Ono thousand eight hundred and eighty, and made between the said Edison 
Telephone Company of London, Limited, of the ono part, and us, tho said United 
Telephone Company, Limited, of tho other part, and duly registered in tho Great 15 
Seal Patent Office, the said Edison Telephone Company of London, Limited, 
assigned to us, tho said United Telephone Company, Limited, tho said Letters 
Patent, and the lights and privileges thereby granted, and the same thereby became 
and are now vested in us, the said United Telephone Compnny, Limited: And 
whereas, since tho filing of the said Disclaimer and Memorandum of Alteration, and 20 
very recently, that is to say, about the First March, One thousand eight hundred 
and eighty ono, your petitioners liavo ascertained that shortly prior to the applica¬ 
tion for tho said Letters Patent, a description of tho Invention of the said Thomas 
Alva Edison, in so far ns it relates to [the electro 'chemical receiver ns covered by 
the third claim, was published in an American nowspaper and afterwards copied 25 
into an English pnper, and we are advised that, although there was no Invention 
by any one in England, or elsewhero, other than the said Thomas Alva Edison, of 
the said part of his Invention, the nforesnid publication renders doubtful tho 
validity of the said third claim, and wo are desirous of striking out the snmo, and 
of altering tho numbering of tho succeeding claim accordingly, in manner more fully 30 
hereafter appearing, NOW KNOW YE, that we, tho said United Telephone 
Company, Limited, by and with tho leave of Her Majesty’s Attorney General, 
and for the reasons aforesaid, do alter the said Specification by striking out of the ’ 
Specification as amended by the said Disclaimer, printed by tho Queen’s Printers, 
and published at tho Great Seal Patent Office, in One thousand eight hundred and 35 
eighty, the whole of the third claim, comprising linos twenty to twenty four, both 
inclusive, on page 9. Wo also strike out the word « Fourth " at the commencement 
of fine twenty five of the said page 9, and substitute therefor the word “ Third.” 
We also desire to correct a clerical * occurring in tho said amended Specification 
by striking out the figure “ 2 ” which follows the reference letter “ c ” in line forty 40 
therefor the S figure ?|» aid printed copy ° f tlle said Specification, and of substituting 
And in order that the effect of the said Disclaimer may be clearly understood, 
lS X S e ”" t0 J, Oopy , ? f ‘ ho said Specification, as it will appear when so 
amended, the preamble and testing clause being omitted. 45 

PatentiinrW ^ E 0 xo(! 1 llo “ t Ma j e3t y Queen Viotoria, by Her Royal Letters 
WestminS ^ °/ T G , reat Britain and Irola “ d * faring date at 

eioht hundred lhlrtleth , day of Jul y. in «»e year of our Lord One thousand 
Hmsalf H«r L d T enty S6Von ’ ,n tl10 forty first y 0ar of Hor reign, did, for 
Menlo Park* iiTtlfp t successors, give and grant unto Thomas Alva Edison, of 50 
admtaistrate™ S S - ‘ £ No ' v Jersey, United States of America, Ids executors, 

aS shtS ° f „ a331 f“’ or suoh . others M he, hie executors, administrators, or 
«mfs thereaftofl ^ ‘“J? agreo Wlth « and n0 othors - from «uio to time and at all 
make !! ™ during the term therein expressed, should and lawfully might 
Ireland tb ^r 0180 * and vend within the United Kingdom of Great Britain and 65 
Ireland, the Channel Islands, and Isle of Man, an Invention of « Impkove^OTS iff 


nM.m.cAc A.D. 1877.—N° 2909**. 3 

fjjimi's lmyls. in Controll ing bg Sound ike Transmission of Electric Currents, i-c. 

Instruments for Controlling by Sound tiie Transmission of Electric 
Currents and the Reproduction of Corresponding Sounds at a Distance,’’ 
for anil during tho term of fourteen years thence next ensuing: And whereas, m 
pursuance mid performance of a proviso in tho said Letters Patent contained, tho 
, J n j,i Thomas Alva Edison did, within six calendar months next after the date of 
' tho said Letters Patent, cause a Specification in writing under his hand and seal, 
numartitier to particularly describe the nature of tho flam Invention, and m what 
manner the snmo was to be performed, to be duly filed in the Great Seal Patent 
Office • And whereas, by an indenture bearing date tho second day ot August, 
10 Ono thousand eight hundred and seventy nine, and made botwcon the said Thomas 
Alva Edison of tho ono part, and us, the Edison Telephone Company of London, 
Limited, of the other part, the said Thomas Alva Edison assigned unto us, the 
said Edison Telephone Company of London, Limited {inter alia), tho said .herein¬ 
before recited Letters Patent, and nil rights, powers, authorities privileges, 
15 advantages, profits, emoluments, and benefits, to the said Letters Patont apper- 

And whereas, 8 sinco tho date of the said assignment, we have been advised and 
have ascertained that the said Specification contains matters which arc of doubtful 
novelty, or which are not of Bufliciont practical value and utility to justify their 
i0 retention nnd we are therefore desirous of striking out the whole of the claiming 
clauses contained in the said Specification, with the exception of the first, second, 
eighteenth, nnd twentieth claiming clauses, nnd of striking out parts ot tho 
description contained in the body of the said^Spocification, and also of otherwise 
altering the’“aiTs^ Torc'°fully hereafter appearing. 


altering the Hind Specification 
25 NOW KNOW YE, that we, the said Edison Telephone Company, of London, 
Limited, by and with the leave of Hor Majesty’s Attorney General, and for tlio 
reasons aforesaid, do alter tho said Specification by striking out of tho sme 
Specification printed by the Queen’s Printers, and published at the Great beat 
Patent Office in One thousand eight hundred nnd seventy nine, the words the 
30 Bame,’’ which occur on page four at the end of lino nino and tho beginning of line 
ten respectively, and substituting therefor the words " a corresponding \\ e also 
strike out the word “the,’’ which occurs between the words “ and and electro 
on the said pa«e, lino twenty two, and substitute therefor tho word an. )VO also 
insert between the words “ the ” and “ instruments,” which occur on the said page, 
35 line twenty five, tlio word •' transmitting," and we strike out the letter s at the 
end of the said word '■ instruments." We also strike out tho word " are, which occurs 
on the same line, nnd substitute therefor the word ” is. We also insert between 
the words ” in ” and “ Figs.” (an abbreviation of tho word Figures), which occur on 
the same line, tho words “ section in,” nnd we strike out the letter.' s in the said 
40 word "Figs.” We also strike out tho words commencing with “and on the said lino 
twenty five, nnd ending with tho first word “ instrument” on line twenty six o \ 
said page four. Wo also strike out tlio words “ or the,’ winch occur between the 
figure "2” nnd tho word “receiving” on the said lino twenty six, and substi 
therefor the words » represents a.” We also add after the word “ instrument ..at tho 
45 end of tho said line twenty six the words "which may be employed with it. 

also striko out tho word “ The ” at tho commencement of line, twenty seven on the 
said pago four, and substitute therefor the words 11 Referring to Figure ie j 
Wo also striko out that portion of tlio Specification commencing with tho norus 
” In Fig.” on page five, lino forty one, and ending with tho word sound on page 
50 six, line three wcalso strike out that portion of the Specification commencing with 
the words “I also” at the end of line eight, and ending with the words the lino 
on lino eleven of the said page 6. We also strike out the whole of lines twenty four 
to twenty eight inclusive on the said page 6. We also striko out the voids to 
record,” which are repeated on line thirty five of tho said page 6 and add tlio 
55 loiter “ s ° to the word " rest, 0 which occurs online of forty seven of the said page 6. 
We also strike out of page 8 lines thirty seven to forty two inclusive and lines 



















4 A.D. 1877.—N° 2909**. »■*»«•.* 

Edison’a Impls. in Controlling by Sound the Transmission of Electric Currents, Ac. 

forty six to fifty three inclusive. Wo nlso strike out of page 9 linos eighteen to 
twenty three inclusive nnd lines thirty seven to forty ono inclusive. Wo also strike 
out of pngo 10 linos sovontoon to thirty seven inclusive. Wo also striko out of 
page 11 lines ton to thirteen inclusive and linos forty four to fifty seven inclusive, 
and wo add at the end of lino thirty sovon of tho said pngo clovon after the word 5 
" named " tho words following“ I would observe in conclusion that I do not claim 
generally tho transmission nnd reproduction of sound by increasing and decreasing 
tho resistance of tho circuit, nor do I claim separately any of tho parts or arrangements 
hereinbefore described and illustrated in tho accompanying Drawings, except as 
hereinafter mentioned ; but wo nlso striko out tho word “ an,” which occurs between 10 
tho words “of” and “electric” on lino 42 of the said page 11; and wo add tho 
letter “ s " to the word " regulator,” which 000111*8 on tho same lino 42, to make it rend 
"regulators,” and after tho said word "regulators" wo insert tho words "sub¬ 
stantially ns hereinbefore described.” Wo also strike out of pngo 12 lines ono to 
thirty inclusive, lines thirty six nnd thirty seven, and lines forty two to fifty six 15 
inclusive. Wo also striko out the word “ Eighteenth," which occurs at tho com¬ 
mencement of line thirty ono on tho said page 12, and substitute therefor tho word 
“ Third." We also strike the word Twentieth, which occurs at tho commencement of 
lino thirty eight of tho said pngo 12, and substitute in therefor the word “ Fourth.” 

We also strike tho work “ or,” which occurs on lino thirty nino of tho said page 12, 20 
and substitute therefor the word “ on.” Wo nlso striko out of page 13 lines 
one to fourteen inclusive. And in order that tho effect of tho said Disclaimer 
may bo clearly understood, wo annex hereunto a copy of tho said Specification 
om'tt n PP ear w ^ en amended, the preamble nnd testing clauso being 

This Invention relates to that class of electrical instruments in which sound 
becomes one of the elements in tho transmission of tho communication, and a corre¬ 
sponding sound is produced at the receiving station, so that oral communications 
can be sent by electricity and clearly distinguished at tho receiving station. 

Musical tones may nlso be sent, but my present Invention is especially available 30 
in transmitting and receiving oral communications. 

In transmitting musical tones tho respective notes each linvo a definite period 
1 „r:V l nitl0 "'* hen00 *u ei ' e , 13 a res P° nso at receiving end from tho notes 
,* ,;nV m . tlme , Wlth . tho e,ectrio pulsations sent, but in speaking there 
inflection! of” he voice'” ,,mS ' C '' t0ne ’ bUt COn3iderab,e in tho modulations nnd 35 

tvmnaTbv' CSent v Ven * t! ? n 1 ” nko U8e of tha Orations given to a diaphragm or 
ensFonnnLTr Dg t a ? s ° nant caSQ to produce a rise and faU of electrical 
tc pon the line, with such accuracy that tho electric pulsations or waves will 
mnnnetnt ti,° at “ 0S P IlBrl ° ?°«nd waves produced by articulation, and an electro 40 ' 

S to fenmdn J e H elVln i? n™ T* 1 rcs P ond to tho (ilectrio wav <* ™ such a manner 
lepioduce the articulation by acting upon a resonant plate. 

FiJure 1 ThTf 7 T fc “V n “ “ m P‘ ote form is represented in section in 
with "it. d F ° 2 r ° proSontsa ruceivir| g instrument which may be employed 

Referring to Figure 1 , the resonant tube or box a is of a size anil slinne adanted 
LtL SF n e ? Y 0 ’ t, ‘° f am ° llavin e an opening at one end or sWc and a 
voml act anl d lhese r a en ? S tl i agal " sfc tho souud wavos from 11,0 human 

of pioduri n “I , I. '? f 010n , t,lafc th0 drophragm receives is the mean, 

set forth so°th, t tl,« b ff of l , olootri ° tenaton on ll “*‘ lino by tho devices hereafter 5 " 
less m° t o t .i lht . 17 , B ?° ,mcctod t0 11 0 11 0 1 rvill transmit a greater or 
magnetism of”110 cores^id in so° , 11 ? a S Ilek TO ’ 2 . and incrcaso or lessen the 
sound corresnondino* to’n » r t < }? lug , ac , k u P on a roson “ut plate 0 and dovolop 
Tim „„„ ’1 r ° to , simulation at tho transmitting station. 
dovelopLthe sImfmanv hUS r^° SCr F bed pet ' Vndo my entil '° Invention, but in « 

hcon made, which I wM £ro CC edtottTrih m ° dification9 and variations have 


tiiirtaimw.ec. A.D. 1877.—N° 2909**. . 5 

i„. Controlling bn Sound th e Transmission of Electric Currents, Ac. 

mss?— ssrtii as»ys.fi 

. rito the nfato cSst thenar; this brings tho sound close to the organs of hearing, 

5 and* the°resonant plate touching the ear increases the distinction of the sound, and 

and aho the hearing instrument as a fixed resonant tube, these being variable to 
10 siiit the ^crsons or t P requires separate consideration 13 the peculiarity 

ofIhorcsonaWt'tubo for"^ voice; Itaivo experienced g p° a ^^^^0*from^tho°fart 

resonant box may bo contracted to about halt an inc character of the 

same purpose. Tho next feature requiring consideration is the character ot 

diaphragm in the speaking instrument me tals, horn, vellum, 

30 vibrations, and being of a laminated character c j* J , accurilcv to the 

thickness, and when secured at its edges responds f , g tho 0 i iange3 of 

sound vibrations, and does not require to be strained - f ; lr n “® r ““ r t e, u ta0 n °‘ the ° mica 
temperature and atmospheric condition have little or no oiiect upon tne mica 

or less resistance in tho line. This resistance may P m0s fc delicate to 

have Bhown several which will hereafter bo name , . .. suc h ftS particles 

40 be small bunches or tufts or discs of some conductmg 

of silk, and an iutennedinto1 conducmg to tho 

call an electric tension regulator, it. is more or icaa i . teng j on ^ 

vibrations of tho diaphragm or tympan, and the 1eierttm e small 

it is compressed, or lessens as the hbro expands. „ r Tb i S variable pressor*, 

45 roll t between the delicate diaphragm spring u^Hguro , b 

adjustable by screw or otherwise in .the electric ouxu.t a «ns gonftjr ^ 
within a cavity in said presser v, ns u Fj S«vo lj there ^ ^ flbro 

piece w to tho diaphragm b with a pieci0 of plutini‘ » . g ade by a thin strip 

50 5 JtSfTS SISK Sing t*• -A ftom th ° Un ° ° r bl ' Uery 

■SfliS. 1 . ■~.jv r b Sg a *S£? 

metal, or smilar material, or by a deposit of P tbu oendueting 

particles of conducting or semi-conducting material mixed, w‘tli it, 

55 power varying with the density of tho tuft «« hranch 'ef fib ■ h0 cured by 

The delicato spring u, Figure 0, upon tho mica diapliragm <•>» ) 
solder passmg into fine holes bored in the mica. 





















0 A.D. 1877.—N° 2909**. Dimmer,* 

Edison’s Fmpts. in Controlling by Sound the Transmission of Electric Currents, ic. 

In some cases I make use of a variable rosistanoo resulting from greater or less 
intimacy of surface contact, such as would result from a disk covered with plumbago 
placed adjacent to a diaphragm also covered witli plumbago or other semi-conducting 
material, so that the proximity or extent of surface contact will produce rise and 
fall of tension, the respective parts being in tho telegraphic circuit. { 

I sometimes perforate tho diaphragm 10, Figure 18, and place a strip of elastic 
material 40 across said diaphragm over the hole, and upon this a piece of foil, so 
that the same responds to very weak vibrations, and in some instances two or 
more diaphragms are provided at different sides of the resonnnt box, each with its 
own tension regulator, the diaphragms being either the same or of different sizes, ID 
characters, or tensions, so ns to respond to varying sounds or acoustic condition, 
tho various tension regulators being all in tho electric circuit; this will produce 
greater riso and fall of tension for longer lines in consequence of the diaphragms 
acting simultaneously on tho tension regulators. 

In some instances it is preferable to make the mouth piece of the speaking 15 
instrument sufficiently large or flaring to receive all tho sound vibrations, whether 
coming from the mouth, nose, or throat. 

The tension regulator formed of fiber and conducting or semi-conducting material 
may be either dry or moistened with a liquid. 

In some instances I make use of tho best quality of lamp black retained within 20 
a case to form the tension regulator, tho circuit passing through the same, and the 
rise and fall of electric tension resulting from tho compression of the same by the 
movement of tho diaphragm. 

I nm enabled to record the sounds produced by tho human voice or otherwise 
by causing tiie movements of the diaphragm to bo registered on paper or soft sheet 25 
metal, and then the paper may be used in an instrument to reproduce the sound 
upon a delicate diaphragm by giving to the Bame a vibration similar to that 
originally given by tho voice. 

h, Figure 4, is tho indenting transmitter, the diaphragm having a knife edge 
point ; z is the paper which has previously been passed through a machine to raise 30 
a V shaped rib 6. Tlio movement of the diaphragm of h when the drum is in 
motion causes tho knife edge point I 1 to indent tho raised rib to vurying depths 
according to the amplitude of vibration of tho diaphragm, thus these indentations 
represent accurately nil tho tones and varying inflections of tho human voice. The 
paper after being indented is passed through a second apparatus n, Figure 5, almost 35 
similar to h. A spring 9 has a knife edge which rests upon tho raised indented 
,' , u . 10 s p™>g being connected to a delicate diaphragm 10 by a string or straw, 
llie indented rib reproduces in the spring 9 the movement of tlio indenting point 
and either by direct action or through tho vibration of a string conveys tho samo 
motion to the diaphragm of n, and reproduces previous sounds. If theso sounds 40 
• l i tr .‘“ 13mittc 1 d over a telegraph lino, the diaphragm 10, see Figure 6, is 
provided with a cork disk w, and fibrous tension regulator t before described, to 
pioduce the rise and fall of electric tension on tho line. Tlio sound may ho 
“ re P roscntcd , in figure 7. The diaphragm of A operates a very 
acrnrrflnw in .P 311 0j and causes the continuous lino to be wide or narrow 45 

according to the amplitude of vibration of tlio diaphragm. Tho ink used should 
ry quickly and tlio strip may be passed at any time thereafter through the 
C m F ‘S Uro 8 - beneath the a ™ 12, lmvinga point or points resting 

I S 'T °™>. 13 connected with a resonant diaphragm, and the ink marks 
thh wfll if 3 ‘: lCt i° n accordin S. to tho broadth and amount of ink deposited, 60 
diaphragm of ft 1 ^ dlaphra S m o£ n vlbratin S and reproduce tho vibrations of tho 

wotld ^la U rnri?iS« 5B w li ?“ J ould be to coat tho P«pcr with a substance which 
Hurinf nrcvIZl thu ° u 10t ‘.°?* " °Y en rou 8 b ' ,nsized P a P°v might bo used, and 
paper to be made burmahed P° mt ™ tb ” Sat would cause the surface of the 65 

P P to be made smooth more or less according to the vibration of the diaphragm, 


f , _ A.D. 1877.—N° 2900**. 7 

Edison's Impls. i n Controlling by Sound the Transmission of Electric Currents, d-e. 
and the difforonco in the surface of tho papor would produco a responso of the 
IC< I somcthnes'arrango tho battery in connection with tlio transmitting instrument, 

5 M /f is'tho" resonant chamber, at the end of which is tho diaphragm 10, and at oacli 
side of this diaphragm thoro are springs <?, c 3 , having points made of compressed 
plumbago mixed 'preferably with gum rubber, but any substance not liable to 
rapid decomposition, or tho olostio or fibrous tension regulator aforesaid may bo 
used. These points face each other on opposite Bides of tho dinphragm and make 
10 contact with platina foil disks secured to tho diaphragm. 

Tho spring c 5 passes through a bolo or small slot in tho side of the chamber h ; 
rfi <p are tho main batteries ; the battery d 3 1ms zinc to the line or spring c 3 , nnd the 
battery <P has copper to the lino or spring c\ When tho springs c J and f are adjusted 
to mako contact with the dinphram cqunlly no currant passes to the line, but when 
15 the diaphragm is vibrated its movement to ono side, say, c s , causes a greater 
pressure upon tho plumbngo on that spring nnd a loosening of tlio pressure on the 
plumbago on c\ hence tlio balance of tho batteries c= and <? will be destroyed, c- 
having tho advantage will send a negative current to line; upon the return of the 
diaphragm tho battery currents will again neutralize each other. The vibration of 
20 the dinphragm to the othorBide causes the pressure to bo reversed, and tho battery a 
will send a positive current to tho lino. . 

As tho tension regulator of fiber or of plumbago decreases and increases its 
resistance enormously undor slight changes of pressure, it follows that the strength 
of the electric waves will bo in proportion os tho speakers voice is strong or 

In Figure 11 is shewn tho contact spring, which may bo used adjacent to the 
diaphragm at ono or both sides thereof; e 1 is a U shaped spring secured to the 
screw c*, which is adjusted back and forth by the thumb nut e 5 ; e“ is the pillar 
holding such screw ; r is a piece of Boft rubber or equivalent substance placed between 
30 tho prongs of the Bpring e 3 ; e 7 is a wire or band which serves to bind the prongs 
tightly against the rubber r, so ns to prevent tho prongs acting ns a tuning fork and 
transmitting harmonic vibrations notdcsirnblo ; r* is tho plumbago contact point. 
The object of the U spring and rubber is to present a semi rigid point for contact 
so as to prevent n rebound nnd allow of a slight yield when the plumbago is pressed 
35 by tho diaphragm. . r 

In Figure 3 tho diaphragm of tho receiving instrument is vibrated by a strip ot 
paper chemically prepared, that is, in motion, tho pulsations of electricity passing 
over tho lino and producing more or less friction betwoon tho paper and an arm 
upon the diaphragm. , „ ., , , 

40 Tho resonant box or chamber n is provided with a diaphragm as aforesaid, and to 
raid diaphragm an arm Id is connected. At its outer end is an adjusting screw h 
that presses upon a platina faced spring id that is secured to this arm, nnd said 
spring rests upon the strip of paper that passes over the drum Id. 

The paper is moved slowly by rotating the drum A*, nnd tho waves of electricity 
45 coming over tho line pass through tho arm Id to the platina-faced spring h , thence 
through tlio pnpor to tho earth. , , 

If a negative current passes in tho opposite direction nearly all friction between 
the platina plato and tho paper censes, nnd the diaphragm of tho resonant box n 
retains its normal position. , , ,, 

5* When tho positive current passes through the same channel tho normal friction 
of tho paper is augmented, and the chomical surface acting upon tho platina 
spring arm serves to give a forward movemont to tho diaphragm of tho resonant 
box. 

Thus tho mechanical force applied to move the chemical paper or surfaco acts 
5o with the electric current to produce the vibration of the diaphragm of tho resonant 
chamber, nnd theso vibrations will correspond to those of the diaphragm 6 made by 
speaking in tho tubo a. 






















8 A.D. 1877.—N° 2909**. w«>.i»»r,M. 

Edison’s Impts. in Controlling by Sound the Transmission of Electric Currents, <t-c. 

Tho principle of this method of obtaining motion by electro chemical decom¬ 
position is that avium a moving surface is in contact avith a slightly yielding 
substanco the tendency is to move the latter by and avitli the former. If the 
circumstances of contact arc varied the adhession of the surfaces will bo sufficient 
to cause the moving surface to movo the yielding substanco or else to cause the 5 
yielding surface to slip moro freely, and by its spring go in the opposite direction 
to the moving surfaco. 

Tho passage of electricity at the surfaces in contact will clmngo the frictional 
adhesion, make it more or less, according to the substances employed. By balancing 
tho mechanical forces, so that avhen the surfaces in contact nro not electrified the 10 
moving surfaco carries with it tho yielding surface, and avhon electrified tho 
yielding surfaco slips back over the moving surface a mechanical movement is 
obtained that is dependent on tho electrical condition of tho surfaces in contact. 

When it is requisite to obtain very perfect articulation, and when loudness is 
not essential, I adopt a modification shewn in Figuro 12 of the device for com- 15 
pressing and expanding the tuft of conducting fiber, which modification consists in 
placing between the diaphragm 10 and the fiber t a vibrating tongue 21 of steel 
permanently mngnetised, and arranging it to act in the samo manner upon the 
tension regulator t as if it was the diaphragm; I replace tho cork upon tho 
diaphragm by a thin armature of iron 22, which is in close proximity to tho 20 
magnetized tonguo, which tongue is secured at one end like an acoustic reed. In 
this position the diaphragm is free to move, and at its approach to and recession 
from the mngnetized tonguo causes said tonguo to follow its movements by 
magnetic attraction, and thus the tongue is mado to perform wliat the dinphrogm 
previously performed in varying the tension of the olcctricity on tho lino. 25 

A plate supported eccentrically and free at its edges when placed in tho speaking 
tube responds advantageously to the tones of the voice. Tho circuit with this plate 
is completely through one or more tension regulators placed around its edges. 

In practice I combine with the speaking or telephonic apparatus signal boll3 so 
arranged that when the telephone is not in use tho line is thrown upon the boll by 30 
a switch which also acts as a call on the bell. 

Ono feature about the bells is that tho magnet which serves to actuate the bells 
is made of veiy high resistance, using preferably Gorman silver wire in tho helix, 
and thus serves to prevent a rapid consumption of battery power. A large number 
ot telephonic wires may be worked from one battery if theso bells are used. 35 

• *i ° . * n( l°pt for coating nonconducting substanco with metallic substance 

is the reduction to the metallic state of metals from their salts by exposing them to 
the fumes which arise from the moist phosphide of a metal such as phosphido of 
calcium; or by placing the silk, for instance, in a scaled tube provided with metellic 
electrodes, and volatilizing tho electrodes by tho passage of electric sparks, such 40 
-latihzed metals settle upon and coat the silk. ‘ 

indnlli” 1 loudness is desirable, us in factories, tho tympan of the receiving 
instrument may bo made to control nr - 1 -* - —-• • . • 


- -- *•“ “if valve of a reservoir in which air is stored 

under a regulated pressure. 

Th?s l, dh!nhr l i 0We< l tO aot with great power upon a local diaphragm. 45 

WnTT t0 , ? bta,n olo , ar B0Unds - requires a damper to check prolonged 
? ,n u ? 10 da ™P ed b y holding the fingers against it or by a tightly 
agatas^tft d r “ bbmg a S ,mi8t lfc by a screw provided^ with a rubber tip held 

dianhZm 0 SSrrJ , mako a reoord o£ tho fl °uud by the movements of the 50 
MfiW tUu . t Purpose a strip of paper moved along regularly between 
fine wire of soft and IS, and there is a smooth thread or 

alone with it ^ 3 ? between tho paper and tho upper roller 25 and moving 

ro * • i . 1 ,‘ e dla pbragm to of the resonant box is connected by a delicate 
bewVfork « eve l 'tw 01 V Vil ; e l S r^ 0 tbe bi S ht of tho roller as possible, there 55 
mad! “n the thread cou gh wl »ich the thread passes; hence deflections or bends are 
mado in the thread or wire just before it is embedded into tho paper by the 


- A.D. 1877.—N° 29 09**. __9 

r,„w„. in Controlling bn Sound the Tran smission of Electric Currents, .to. 

pressure of tho rollers. This may bo used to reproduce tho sound by vibrating a 
resonant diaphragm by the undulations of tho groovo mado by tho thread 

^By placing the fibrous tonsion regulator within a smaU band of India rubber the 
samo is rendered more clastic, nnd the fiber is allowed to expand by the heat of tho 

current without altering the electric tension. ...... , , 

In some instances the diaphragm should be free to vibratei without b «^8 cbeakad 
by contact with any stationary substanco. I provide for tb a , b f r , ' ,Aber or non- 
dinnhiaem or tympan 10, Figure 17, a small cylinder t\ of hard rubber or non 

„ disk «.« 1»»rr: 

regulator as the diaphragm is vibrated, and hence the 

over the liine in harmony with tho vibrations Nearly the sanie ofhet is produced 
by connecting tho disk t» to a yielding spring t ‘ that extends 
edge of the diaphragm to tho other, as seen in Figure 1C. This construction of 
20 tension regulating dovico is especially available with large diaphragms. 

In some cases I use a soft rubber diaphragm immediately in contact with the 
transmitting or receiving diaphragm, so ns to check or dnmpon nny pro o 
false vibration, and render tho sound more clear and freo from prolonged • 

In preparing tho tension regulator I hud m some c s ■ P 

25 to use lampblack mixed with pure lumbago, amorphous phospl orous, aiid a c y 
small amount of nonconducting material, such ns rubber dissolved i 

"'inFigure iTlhTvo represented tho circuit as passing though the di “P b “S™ “■ 
tension regulator t, and a Duluc's dry pile battery V, P, B,toit heearth ri. 

30 battery is composed of about throe hundred pairs of paper disks coated with silvei 

nn F^^llZ E rLico before mentioned for intensifying y the sound ; 
10 is the diaphragm vibrated by the sound; 42 is a valve moved by sue, 
diaphragm; 43 is a resorvoir containing nir under a given pressure , b • 

35 diaplirftgm against which tho nir allowed to escape by the vn vo a * . 

tension regulator to transmit tho electric pulsations, or n lienr if, 

T SV10. 1SS? 

screw and local circuit containing tho battery B passing o :.J!i uc f: on 
40 induction coil 49, and there is a key 50 in the same circuit. A secondary indue on 
coil 51 is in the line circuit, nnd is influenced electrically by tho change of tension 
in tho local circuit by tho vibrations of tho diaphragm 10. 

The secondary coil is sometimes required with many l&y? ra ® .. . 

up a current of high tension ; to overcome tho inductive effect from the «nci 
45 being adjacent to each other, I place the receiving instrument at the distant station 
between the induction coil and the earth ns at R, and use an electro o : n 'tho 
with polarized armature to strike a bell; this will respond when tho key oU ... tho 
local circuit at tho distant station is opened and closed. , , , , .. 

In Figure 25 a similar induction coil 49 and local circuit is represented, but the 
50 tension regulator is mado of platina foil upon the surfaco of two so ..j 

one on tho diaphragm, tho other on tho adjusting screw. Ail:iunlt and1 rl. ost„t 
atR' servos to prelong tho magnetism in theinduction coil, and thus eiumea 
gradual rise and fall of electric tension in tho hno instead of a cos 
tamo when tho platina surfaces separate, and at tho receiving d aphiagm c t 

« rise and fall of electric tension in the lino and its helix, acts upon «“ 

niagnet to produce tho vibrations of the diaphragm c,, and y ®Lacd of 

around the helix and placing therein tho secondary battery S, B, composed ot 
























JSdison’s Impts. in Controlling by Sound the Transmission of Electric Currents, <Cu 

metallic plates in acidulated water the action is rendered more uniform and the 
sound distinct. 

When the dinpliragm is arranged, as in Figuro 26, to act upon a 'spring 66 
through an intervening piece of soft rubber, said spring 66 produces rise and fall of 
electric tension, by employing a range of resistance 67 with spring tongues adjacent 5 
to 6G. The greater amplitude of vibration of the diaphragm, the moro direct will 
be the electric circuit connections and the less resistance, becauso the circuit will 
pass along the spring instead of going through all tho resistnneo coils. 

When several line wires run near each other tho wire used for tho acoustic or 
speaking telegraph is influenced by induction, and false sounds will be produced. 10 
I counteract this tendency by placing one or more electro magnets 69, Figuro 28, 
in the circuit of the speaking telegraph, nnd one or more electro-magnets 60 in the 


circuit of tho adjacent wires, and bringing tho opposite cores of 60 at such a 
distance from the cores of 59 that a cortnin magnotic action will be set up in 59 
by induction in the opposite direction to the induction currents from the adjacent li 
lino or lines. 

By adjusting the distance between these magnets when tho speaking telegraph 
is not in use until there is not nny sound at tho dinphragm from the induction 
currents, then these currents will bo neutralized, whether strong or weak, and will 
>t produce any false sounds when the speaking tolegraph is in use. 20 

I also employ double coils of wire for the same purpose, one coil being in tho 


I also employ double coils of wire for the same purpose, one coil being in tho 
acoustic wire, nnd tho other in the wire to bo compensated. 

A convenient form for the sound recorder or phonogragh is to employ a 
cylinder 61, see Figure 29, having a helical groove in its surfaco covered with tin 
toil, and the cylinder is revolved regularly by clockwork, and moved endwise by a 26 
screw on its shaft, so that the indenting point P from tho diaphragm 10 of k will 
be always in line with such groovo; hence tho vibrations of tho diaphra»m will be 
“ ed b ,y indenting the Ml into tho groove, and hence tho same sound will bo 
7„ rodu „ ced by ‘ho p o in t f- of the hearing instrument n, giving to the diaphragm 
with sue “point 5 thnt rCSU t fr ° m tbo lndontatioDS of th » foil moving in contact 30 
named/ 0 " 1 m “ y be ° n n flat erooved P Iate < nnd be indented and act as before 

re/roTuctfon^T * H tbat 1 d ° nofc aI “m generally tbo transmission and 

nor do l plabn f B ° unds by ^creasing and decreasing the resistance of the circuit, 35 
and illust a PH r« tely ° f ^ P " ts °'' arrangements hereinbefore described 
£ut I claimas my lSvenS,T DyU,e DraWing8 ' eXCCpt “ mentioned, 


nor r do U I ti 1°“ ° f B0Und , s , by increasin S and decreasing the resistance* ofTh 
nnd illustm/pV^ a fi te y “ ny ° f th ® pn S 3 or arra ngements lioreinbefore 

£utI c]aim? 8 myInt e enZ.- PUDyin8 DraWing8 ' ° X ° ept “ hel ' oin “ ftflr “ 

First. In an instrument for transmit!,inrr nW.rip impute u.. __j _ 


combination "Li til _ instrument for transmitting electric impulses by sound, the 
ns hereinbefore 01 bympan of ? lcotnc tension regulators, substantially 

as set forth. f »r varying the resistance in a closed circuit! substantially 

on^lldingmaTeria? 118p0oifl ? d °f recordi “g ‘ho undulations of the diaphragm 45 
d“ap y Cm^o communW^>o reproduction of sound by such material acting upon a 
subXnTlly as seUeru' *° tbe 8am ° vibrations similar to tba original ones, 

In panipT 8 M • vhoreof - tbe eaid United Telephone Company Limited have 

0 T "“‘r *“ '*» " f ** 

® JAMES BRAND, 

Chairman. 

JOSEPH B. MORGAN, 

Director. 55 

R. H. KRAUSE, 

Acting Secretary. 


m<m’s Impts. in Controlling by Sound the Transmission of Electric Currents, Tc. 

To the Commissioners of Patents for Inventions. 

T hereby grant my fiat, giving leave to the above name d United Telephone 
r mnnnv Limited the assignees of the said Letters Patent, to file in the Office of 
Company, Bimiteu, cn b x nvon tions, with tbo Specification to which tho 
1,10 fTi'ato^the'ato^^v'ritton'^Discirimer ’and Memorandum of Alteration, but 
5 noverthofessupon condition thnt no proceedings for infringement bo takon against 
one in respect of tho first fivo thousand telephone instruments supplied or to 
?" y «iinnlied under tbe contract between the Gower-Bell Telephone Company, 
limited and the Post Master General, dated the 28th March, 1881. Particulars, 
„ if Paired of the marks by which such instruments may be identified to bo 
° delivered to the United Telephone Company, Limited, nnd verified by statutory 

dC Dated°this Fourth day of June, One thousand eight hundred and eighty one. 

Henry James, 
Attorney General. 

15 The United Telephone Company, Limited, accepts and hereby undertakes to 
abWebytoo conditions imposed by the Attorney General and mentioned in the 
above mentioned fiat. JAMES BRAND, 

„ /"T \ Chairman. 

!0 f maica \ G. E. GOURAND, 

{ Tcicpuocc j Director. 

V C ,?K' / R. H. KRAUSE, 

XT’” 1/ Acting Secretory. 

























A.D. 1877, 3i»< July. N° 2927. 


Instruments for Transmitting, &c. Telegraphic Messages. 


(This Invention received Provisional Protection only.) ■> 

PROVISIONAL SPECIFICATION lea by Tliormis Alva Edison at the Office of 
the Commissioners of Patents on tlio 31st July 1877. 

Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United States 
or America. "Improvement in Instruments for Transmitting, Recording, 
j and Receiving Telegraphic Messages.” 

In my improvements a copy of the messago sent by an ordinary koy iB preserved 
nt the sending station, and the message is recorded at the receiving station, and it 
may be recorded at more than one station on the line, and the recorded message is 
10 mi t0 transll ! it U P°'> another circuit, or to repeat the message. 

The record is made by indentations ina sheet of paper, but instead of the indenta¬ 
tions being made in a long Btrip of paper tho record is mado in either a volute lino 
upon a correspondingly grooved disc, or olse upon a sheet of paper in a zig-zag 
line, over a cylinder that is correspondingly grooved. Tho paper is put upon tho 
l, , ? or cylinder in a predetermined position, regulated by register mnrks, so as to 
oo held accurately in plncc, and the indenting point is upon an arm or slide that is 
Kept in position by n corresponding groove, or volute, or otherwise, so that tho 
indenting point is always over the groove in tho metallic disc or cylinder, and will 
undent the paper down into tho groove when the point is pressed upon the paper, 
mo indenting point is operated by nn olcctro-magnot, hence when tho lino connec- 
■°n is made through the electro-magnet there will be n record taken at the sending 
laticn of the messago sent by nn ordinniy koy, and tho samo record will be mado 
t the distant station by a similar instrument. 

in I i y 40 US0 l * ie indented paper to transmit a message to a distant station the 
25 eir al ° 1,m< io to °P en ft nd c ' 080 11 c * rcu ' t breaker in tho lino or electric 

cult, said papor being moved automatically beneath the circuit-breaking apparatus, 
indents*’^ rovorset * 40 wor * c c ' lcu * t by tho projections instead of tho 

moss™ recc ‘ v ’ n 2 or , transmitting discs are usually connected together for long 
usaages, and the circuit connections and clutches to tho actuating gearing are 
I [Price 2d.] 

























2 A.D. 1877—N° 2927. 6 SX 

Edison's Improvement in Instru ments for Transmitting, <tc. Tclegraphio Messages, 

niTftngod no oh to connect with ono and disconnect from tlio other alternately, 
cither with or without break in tho message. 

Tho sheets of indented paper can bo preserved os a record, or used at any timo for 
transmission or repeating tho message. 

A magnetic ongino and govomor aro usually omployed for giving motion to tho 5 
parts that carry tho paper so ns to obtain uniformity of speed, or nearly so, in tho 
different instruments, and tho lino is provided with local circuits, soundors, or calls 
for facilitating tho business as usual; and in eases whero it is proforrod to make the 
record on chemical paper, or by ink, it may bo employed in tho same apparatus. 










A.D. 1878, nth Apinr.. N° 1644. 


Recording and Reproducing Sounds. 


LI ' T 2!!!.v P iT T -fT r a^7 h0 T 8 . Alv '. Edison - of Menlo Park, in tlio Stato of New 
« ... I ’ H'' lt p Statra of „ America, r ° 1 ' tho Invention of “ Immiovements is 

SUCH ItKCOH[f" 00RDIN '° S ° UNDS ’ AND IN RePBODUCINO SUCK SOUNDS FHOJI 

Sealed tlio (itli August 1878, mid dated the 2-Uh April 1878. 



^*XJ?*®RAL SPECIFICATION loft by tlio said Tliomns Alva Edison at tho 
_ Ul,lce 01 tlle Commissioners of Patents on tho 21th April 1878. 

Rhul!° a r a AU ‘ a Edison, of Menlo Park, in tlio Stato of Now Jersey, United 
c TirruiA.? A " 1C1 ' lca - " iMl'IiOVEMENTS IN MEANS KOll RECOKDINO SOUNDS, AND IN 

5 w.pimnuciNa such Sounds kiio.m such Hecoiid.” 
hemuinm S ?. nt ,B y«WomonU mo for more fully dovoloping and perfecting tlio dovico 
Bv 1 u . vcnted hy me, and known as tlio “ phonograph.” 

IS1VO , < '^ I10ril " ent nni1 research I havo boon onabled to obtain very perfect 
1ft 'flu, !„ , to Produce a record in a convenient form for preservation. 

or other v? V J brn , tion ? are mode to movo a point that by preference is a diamond 
lhcntnmu, i y , substance nnd of a peculiar sliapo. Tlio sound vibrations in 
«nno inow«t°i re - Ct i Up . on a diu I )lll ' a S"“ 01 ' other body capable of motion, nnd the 
is pronorlv “ lnt J c, |hng point, and acts as a pliouograph. Tlio indontod material 
15 foil is ni , l 8 nato<1 11 phonogram, and it is preforably inotnllie. Sometimes tin- 
placcd inimi U1 ’“ n a peered surfaco; somotimes a thin shoet or leaf of metal is 
SoinslCL n 10<;u of P a P°r living a surfaco of parafln or similar matorinl. 
steel or iZ, i "! otal 10 surfaco is coppor, nnd whoro a matrix has boon mndo of 
hardened and uLl r •° tyP ° ^ P ° S ^’ ° r otlle ™ iso - u P on tlie Program it may bo 
20 phonogram <umi f ", lprC f 1Dg a sheet or roller of metal, and thereby the original 
for anv rnmm “° 1 T °‘ ll00c lllllc,ill >tely m metal that may bo hardened nnd usod 
Phonetically? “ ° ° neth of timo to ultor tho sontonco, or words, or sounds 
[•Price 10<i] 














2 AD. 1878,-N° 16-14. _ &&& 

Edison’ s Improvements in Recording and Reproducing Sounds, 

Tho instrument or portion of tbo instrument that reproduces the sound from tiio 
phonogram I term a “ phonet." 

In order to facilitate production, use, and preservation of tho phonograms I 
omploy a ring or margin of thick paper or pasteboard, caused to adhoro to tho 
foil or sheet by resinous substance; this is used as a gnugo in placing tho sheet in 5 
the instrument or replacing the samo in tho phonet. I find that a disc rovolved by 
gearing, and a weight or spring, and the movement regulated by a fan or governor, 
is a convenient device for presenting tho surfaco to bo indented to tho phonograph, 
and tho phonograph !b on an arm that swings towards and from the centro of the 
disc, and is guided by grooves or other convenient mechanism. II 

The phonet device takos the place of tho phonograph device when the sounds nro 
to bo reproduced. 

When the sheet of material is wrapped around a cylinder its edges are passed 
down into a Blit and held firmly. Eithor tho cylinder may bo moved ondwiso by a 
screw, or the phonograph or phonet devices be moved along tho cylinder, and where II 
the same sound is to be reproduced periodically, as calling out the hours of the day 
in a clock, or reproducing the sounds of animals in tovB, the phonot is to be brought 
to the place of beginning automatically. 

The phonographic devices omployed by mo aro profornbly a diaphragm of motal, 
against which the sound vibrations act. Sections of rubber tube applied to tho 2( 
surface act os dampers to prevent false vibrations ; pieces of felt or similar yielding 
material may bo used for the samo purpose, and a small delicate hoop of spring 
metal between tho diaphragm and the indenting point renders the phonogram more 
perfect than it would be if tho diaphragm acted upon the point direct. A similnr 
effect is produced by a disc upon tho arm that carries the point, snid disc being so 2i 
close to the diaphragm that the atinosphero will produce the vibrations. 

It is often advantageous to uso a case between the mouth of tho speaker and tho 
diaphragm to gather or hold tho sound, and in some instances tho head of the 
speaker should bo insorted into this case, up through a hole in tho bottom. Tho 
mouth-piece is sometimes slotted or perforated, and has irregular edges to re-inforce 3C 
tho hissing sounds, and sometimes a membrane of rubber or guttn percha is fitted 
to tho teeth, and forms a bog between the lips and tho diaphragm. 

Tho diso upon the arm that carries tho point ns aforesaid may be acted upon by 
a magnet, and tho current through a helix from a diaphragm, or the motion of tho 
arm and points may serve to set up a secondary ourront through such helix in con- 35 
sequence of the motion given by the phonogram to tho point. The arm carrying 
the point in this latter case should bo magnotised. 

The phonogram may bo produced by tho direct action of air concentrated to tho 
Bpot by a funnel terminating with a small hole, tho end of the funnol being almost 
in contact with tho moving surfaco to bo indented. 4C 

When the foil is perforated instoad of indented it can be rolled up in tiio form of a 
horn or cylinder, and revolved, and tho articulation result from air blown from tho 
ond of. a small tuho passing through tho perforations as they are nresontod in 
succession. * 

Loverngo is sometimes omployed between tho diaphragm and tho phonogram, IS 
either to losscn or increase the motion of tho phonographic action in recording, or of 
tho phonetic action in speaking, and for recording qunrtotte, trio, and other 
characters of singing, two, three, four, or more phonographic devices are omployed 
upon ono cylinder or pinto, and tho sounds will be reproduced by corresponding 
phonets; or whoro singing is convoyed through tubes to ono diaphragm tho phono- SO 
b™completoand * * 10 com ' J * Ilod tones, and the reproduction by tho phonet will 

«i,L^5 tbat m Mm a f ri S h , t angles to a diaphragm, with a point resting upon the 
the diaphragm r ° produco tho tonos the weight and leverage of tho arm moving ^ 

a roM^C™ in ] h ® form of a diB0 > tt sheet, an ondless bolt, a cylinder, 

a roller, or a belt, or Btrip, and the marks are to be either in straight linos, spiral, 


A.D. 1878.—No 1644 3 

Edison'a Improvements in Recording and Reproducing Sounds. 

zig-zag, or in nny otlior convenient form, so long ns the apparatus is adapted to 
bringing tho samo into contact with the phonot or speaking part of the apparatus, 
i, and tho reproduction of tho phonogram from a matrix or copy in relief of an original 
phonogram may be made upon a bolt, roller, oylinder, plate, or other convenient 
5 surface. 

For amusomont and instruction this phonograph is capable of oxtended uso. For 
instnneo, a revolving cylinder containing phonograms of tho lottors of tho alphabet 
and phonet koys, with corresponding letters on thorn, can bo used in teaching tho 
alphabet; and phonogram sentences, speeches, and other mattors can he spokon by 
10 the phonot nnd repeated by tho learnor without the eyesight being called into use. 

For amusement or instruction tho phonogram can bo of a dog's bark, a rooster's 
crow, a bird's song, a liorso’s neigh, a lion's roar, and tho like, and tho phonogram 
can bo used in a toy animal with a singlo phonet for tho reproduction of the original 



15 This phonograph or speaking machine applied to a mask producos a semblance of 
vitality if the phonogram is mado to opornto upon movcablo lips by lovers, and in 
the production of such a phonogram a portion of the surfaco is to be indented by 
delicato levers and points, receiving motion from tho lips during articulation; thereby 
a correct reproduction of tho motion of tho lips is obtained. 

20 In connection with tho phonet it is important to avoid tho sound that usually 
results from the rubbing action of tho phonogram upon tiio point. I am enabled to 
provent this by an eloctrio action between tho point and tho phonogram. In this 
ease tho phonogram should be of iron, and tho point of steel and the parts maguetised 
so ns to slightly repel each other; the point will follow tho undulations nnd reproduce 
25 the sounds by tho phonet. 

It is important that tho point used in tho phonot correspond in shape to that of 
tho phonograph, but slightly smaller, so as to follow the bottom of the depressions 
without contact upon the sides. 

The diaphragm or other body employed in the phonot to rcceivo motion from the 
phonogram is connected with a funnel of paper or other resonant suhstanco that acts 
as a sounding board to render tho phonet louder and moro distinct. 






A.D. 1878.—N" 1644. b, 

Edison’s Improvements in Recording and Reproducing Sounds. 


SPECIFICATION in pursuance of fclio conditions of tlio Letters Patent filed by 
tho said Thomas Alva Edison in the Great Soal Pntont Ofiioo on the 22nd 
October 1878. 

Thomas Alva Edison, of Menlo Park, in tho State of Now Jorsoy, United 
States of America. “ Improvements in Means for Recording Sounds, and in b 
Reproducing such Sounds from sucii Record." 

This Invention consists in means for recording in permanent characters th 
sounds made by tho human voice in speaking and singing, thoso mndo by musical 
instruments, birds, animals, or any sound whatever, and in means for reproducin'' 
thoso sounds nt any desired time. ° .. 

The sound vibrations net upon a dinphragm or other body capable of motion • 
•this diaphragm is at the back of a chamber provided with an opening or mouth¬ 
piece, and to this diaphragm an indenting point is secured. This instrument I term 
a phonograph. Tho phonograph is adjusted to position with its indentin'' point 
contiguous to a moving surface covored with a thin sheet or metal foil or other is 
suitable material, or else tho surface with tho motnl foil is stationary, and tho pho¬ 
nograph movable. J 1 

The surfaco upon which tho metal foil is secured is by preference "rooved 
spirally, and tins indenting point indents tho foil in tho lino of this groovo°as the 
diaphragm is moved back and forth by tho sound vibrations; these indentations "O 
forrepreducing the sounds. “ 

or !! OI f ion °i tbe i °' stn " nc ' lt that reproduces the sound from tho 
& nrorided°w7il! l n F h °? et Jt ‘f s!milar construction to the phonograph, 
Dom pi ovnlcd with a diaphragm and point, but tho mouth-pieco is by preference ’>■• 
funnel-shaped to render tho sound loud and distinct. Tho sounds are reproduced by 
beoi'nZ fTr “^‘fi' t0 P'““ 60 tbat 1110 point of its dl.phrng'.nisatthe 
ind S encdfoiHs1?’n T f I,ldc,lt “t'ons, and as the surface containing the 
fmm onc mwFZf m ° f t , h ° P , ' onot » vibnOod by tho point pLng 

irom one indentation to tho next, lienee tiio diaphragm receives the same movement 30 

made by tho'plmnet" wTin''?. mnkine illdc " t ' ,fcions . consequently tho sounds 
W,llb0the8am0 1,8 th0se operated upon tho diaphragm 

the mechanism'for miLdinr? , S , ectl0n ° f ‘>‘0 phonograph and sectional elevation of 
tlio samT I lng tlle surface t0 be indouted; and Fig. 2 is a plan of 35 

pobt? h TKdvnor d0 1 th ° bot >y Portion a, diaphragm b, and indenting 

the' pivoted at 5 & the vertical stud 0, so that 
purpose horoofter explained. 804 lower ^ verticaHy, or moved horizontally for a 

mouth-pFcco of if with bis mouth near 11,0 

and vilLto^ «?d V ,‘ br . a . tions V 511 upon tho diaphragm, 

«... if . r». of metal foil » 


A.D. 1878,—N° 1644. 'B 

Edison's Improvements in Recording and Rep roducing Sounds. ~ 

beneath or behind the indenting point and caused to move rogularly, or tho indentin'' 
point movod over the matorinl; that Bal'd material will bo indonted and form a 
perfect record of tho sound vibrations. 

I will now describo tho moans for sustaining tho shoot to bo indontod, and tho 
5 mechanism for moving tho snmo :—d is a disk or plate secured to and turning with 
tho shaft c, and hinged to this disk is a ring frame/; this disk d has two spiral 
grooves 3,4, in its surfaco.’ There are pins 2, 2, upon tho surfaco of the disk, and 
holes nt corresponding places in tho ring frame ; tho shoot to bo indented is of a 
size and simp to correspond with that of the disk d and frnmo /. and said sheet 
10 has holes in it corresponding to tho position of the pins 2, 2, and these holos form 
register marks in placing or replacing tho shoot upon the disk d, and after the sheet 
is so placed tho ring frame/is brought down upon the sheet mid holds it firmly in 
piaco. There may bo a central oponing in the indented shoot of a size slightly 
larger than tho space occupied by tho spiral 3, and the outer edgos of tho sheet aro 
15 stiffened by a ring of thick paper or pasteboard caused to adhere by gluo or otlior 
adhosivo matorinl. Tho surface of tho disk d is mndo with two spiral grooves 3 
and 4 ns aforesaid ; tho groove 3 is a guide for a pin that is upon nn arm g on tho 
phonograph, mid tho groove 4 is for the indenting point e. As tho disk and sheet 
are rovolved tho groovo 3 causes tho indenting point to occupy a position itnmo- 
20 diately over tlio lino of the spiral 4, and tho indentations will bo made upon the 
sheet of foil in a line corresponding to that of tho spiral 4, shown in Fig. 2. The 
indentations mndo in tho foil aro a complete record of tho sound vibrations that 
noted upon tho dinphragm b, and from this indented sheet, which I term a “ phono¬ 
gram,” the sounds are reproduced. The phonograph is carried outwardly by tho 
25 spiral 3, nnd in so doing tho parts swing upon tlio vortical stud (i. By depressing 
the outer end of tlio lever i tho phonograph is raised so that it can bo swung asido 
from tho disk d to allow of tho ring fraino / being thrown back and tho indented 
sheet or “ phonogram ” removed from tho disk. 

The shaft c is revolved by a weight, or spring, nnd gearing at li, and tho spring 
30 is wound up by moving tho lover k back and forth, which acts upon a rntchot and 
pawl of ordinary construction ; l is a lover provided at its outer end with an inclined 
groove, in which is a pin nn the lever m, and tho other end of this Iovor m is con¬ 
nected with tho coupler m 1 by moving tho lovor I one way or tlio other, the shaft e 
will bo connected to or disconnected from the gearing h, and hence tlio disk d 
35 stopped or started at pleasuro without interfering with the motor. 

As it is necessary that the shaft c should be revolved with uniformity I provide 
a governor at n to prevent the apparatus revolving too rapidly; and this may be 
made us in Figs. 1, 3, & 4, in which tliero aro inotal blocks o nt tlio ends of spring 
arms from a cross head on a shaft that is driven by the gearing h, said blocks 
40 swinging radially and acting against tlio interior of a stationary cylinder^ if tlio 
speed becomes too great, thereby checking the speed by the friction of tiio blocks 
against the cylinder. Those spring arms may bo socured at ono end to a prisinntio 
block as shown in Fig. 5. It is preferable to cover tlio surfaco of tho blocks o next 
tlio cylindor p with felt or similar material that will slide upon tho interior 
4a surface of tlio cylinder p, but produce more or less friction, according to the centri¬ 
fugal action. 

The guide spiral 3 may bo dispensed with, and oither of the dovices shown in 
I igs. C, 7, 8, or 9, made use of, 

. bl Eigs. 0 nnd 7 tho shaft e projects nbovo tho surfaco of the disk d, and there 
50 is a tootli upon the shaft contiguous to a rack bar extending from the phonograph, 
honco end) revolution of the shaft, tho rack bar, and phonograph will bo moved tiio 
spneo of ono tooth, consequently tho lines of indentations will bo parallel and con¬ 
centric to tho shaft e, excepting nt tho places when tlio tootli acts to move tho 
rack bar and phonograph outward or inward. In this case tho spiral grooves aro 
55 cut to correspond to tho feed. 

,,,8. 8 n worm upon tho shaft e acts upon a worm pinion to revolve tho shaft e 5 , • 
nml the worm at tho otlior end of this shaft e 5 acts upon teeth around tlio base of 







_ Edison's Imp rovements in Recording and Reproducing Sounds. 

tho lover i on the stud 0. By this device tlio phonograph will ho moved outward 
gradually, and tho lino of indentations will bo in a spiral corresponding to the 
continuous spiral groovo iu tho pinto d. 

In Fig. 9 tho shaft a is mado with a fusoo at p', nnd ono ond of a swinging arm 
connected to tho phonograph takes against tho same. Tho spirals of tho fusoo 5 
gradually movo outward tho phonograph, as tho disk nnd shaft are rovolved, nnd 
tlio lino of indentations will bo spirally tho same as that mado by the spiral 3. 

In rig. 10 tho shaft e is provided with a scrow pinion meshing with teeth upon 
groove 8 06 * 118 e ' lvos tbo 811,110 movomunt to tho phonograph as tho spiral 

, 111 Fi f- } * t,le g" i(, ° groove 3 for tho arm and pin g is upon a disk <1* upon tho ^ 
smite, but the groovo 3 occupies tho snmo relative position upon tho disk d' ns 
iu gioove 4 upon tho disk d, so that tho phonograph is moved outwardly by the 
g'oovo of tlio disk d 1 , swinging both tho arms g nnd i upon the vertical pivot 0 
instead of tho sheet of metal foil being upon the disk d it may be wrapped upon 15 
the S.® Tn F f 12 - In . , tlli8 0,180 tl10 °y I!ll<l01 - i0 u l ,on a Shaft e 1 revolved by 
o gearing at A 1 , nnd upon said shaft there is a right and loft hand screw at k\ 
The a ool : l,oapondl ng Joublo spiral groove in the surface of tho cylinder q. 

W?. 1 l 0 . n0 S r a p h‘s secured to a shding shaft l\ and said shaft is moved endwise 
slmft ' A l' Jy , tl10 SC1 '° W ^. llctil, e "Pon an arm m 2 that is secured to the said 20 
mode Inirnireilf P 10 a®S^aphis moved m one direction tho lino of indentations is 
oTthe s P erew y i/W !°, ful1 °“ cyli,ldo1 ' * nlld w,10n 1,10 reaches the end 

«tw 1 n SCI ? W lfc ™ ho moved m tho other direction by tho reverse scrow thread 
the first snirn?°i^ >l 'n, •'"'iK 0, aCC ? ,ul s I ,iml lln0 of '"dentations that will cross 

Tl' 1 " Mature is especially available for a phonot where the 25 
so that th wo° y D Or? 18 ^° m0d °[ a " olootrot yP° or other copy of tho phonogram, 
desired. S0Unds may bo rc P roduccd automatically and at intervals if 

. dt , ls prcferablo to make uso of a thin metal platen 2 , seo Fi"s. 13 nnd 14 nivoted 
for securin-Mhe edm? n?"' a , lo 1 n ? i . t , u<lillnI groove in the surface of tho cylinder q 30 
Tl e o of°tl s l g t„ 5 ? d lmd lloIdin g ^ securely upon said cylinder* 

i.,»SrttaX5«' ■" “ ■!*» »«• 

$ :£: u"„t zhs$ Sst M 

sheet of foil is to be indebtedXJR ^ F™, 0,0 P ho ?°8 rB I* if a now 

accomplished by raising the arm o' I ? * boon removed. This is readily 

“'luRglni’e 0 ^'^ 1 ' 1Ve ,° bo 1 ' 1 "ved bal 0 and forth '° ” W * 1 ^ 45 

as in Fig! I b t't'Xft 1 ”' "a Sn"”!, horizontally instead of the cylinder,?, 
hence tlfo phonlXI to I n , W 1 ,th / 1 BC }™ lllr ? Ild 1,1 «» d i'-°ction only, 

from the screw 7c 1 . 1 lt,onw * ^ uuul aftor ^ l ° arm o l I ms been raised 


indmulfg'pliriom tho cvUndf ap1 ' T wiug up , on tho 8 > mft 1 ‘ to raise tho 50 
sheet of foil, and there s a sYon ’Vr nnd ,. rill ?. w tho removal or insertion of a 

when brought down to indentUm foil 01 “ djUstlng tho P 081t,0n of tho phonograph 

bo swung\orizontallynway'from tlio e V P Y an r an , 1 ? pivolod at 9, so that it can 
adjustable stop 8 is also provided * W 3 f ° r th ° pul 'P 080 aforesaid, and the 55 
Thus far I have described thi ••phonograph” or instrument upon which the 


Spodfiauion. A.D. 1878.—N° 16U. >f 

_ Edison's Improvements in Recording and R eproducing Sounds. 

sound vibrations act, and which instrument nets to indent tho sheet of foil and 
produco tho •• phonogram " or record of such sound vibrations. 

Mechanism has also been described for prosonting tlio sheet of foil to bo indontod 
by tho phonograph. 

■6 I will now doscribo how tho sounds nro reproduced from tho phonogram. 

If it is desired to roproduco tho sounds from tho phonogram in tho snmo instru¬ 
ment in which tho phonogram was produced it is only necessary that tho indenting 
point c bo made to travorso tlio lino of indentations in tho phonogram, nnd that a 
funnel-shaped month-piece, shown by dotted linos in Fig. 1, be added to tho phono- 
10 graph to aid in increasing tho loudness nnd distinctness of the sound. Tho instru¬ 
ment in this form I term a ‘'phonot." 

In tho instrument shown in Figs. 1, 2, G, 7, 8, 9, 10,11, 13, 14, nnd 15, tho 
phonot requires to bo positioned by hand, as before explained, in order that tho 
point c may bo placed at tho beginning of tho spiral lino of indentations. As 
15 the point c passes from one indentation to tho next, either by tho foil beino 
moved beneath said point, as in Figs. 1, 2, G, 7, 8, 9, 10,11, 13, and 14, or by tho 
point moving over tho foil, as in Figs. 12 and 15, tho diaphragm b receives a move¬ 
ment corresponding to the depth of the indentations, and corresponding also with 
the same movement it received from tho sound vibrations when making those 
20 indentations, hence nir waves will bo produced by tho movement of the diaphragm 
that will make sounds by passing through tho mouth-piece of the plionet that 
will be exactly tho same as tho sounds that acted upon tlio diaphragm of tho 
phonograph. 

The material upon which the record is made may bo of metal foil, such as tin, 
25 iron, copper, lend, zinc, cadmium, or a foil mado of composition of metals. 

Paper or other materials may bo used, the samo being coated with pamfine or 
other hydrocarbons, waxes, gums, or lacs, and the sheet so prepared may itself bo 
indented, or tho material, say paper, may be made to pass through a bath of hot 
paraline nnd thence between scrapers. Thin metal foil is now placed on tho 
30 material, nnd the sheet passed through rollers, which give it a beautiful smooth 
surface. The indentation can now be mode in tho foil, nnd the pamfine or similar 
material, nnd tlio indenting point, does not become clogged with the pnrafino in 
consoquonco of tho intervening foil. 

If tho copper foil, or tin foil with copper surface is used, aud a matrix of iron or 
35 steel mado by electrotype deposit or otherwise upon the phonogram, such matrix 
may bo hardened nnd used for impressing a sheet or roller of metal ns hereafter 
mentioned; thereby tho original phonogram can bo reproduced indefinitely in 
metal that may bo hardened and used for any reasonable length of timo to utter 
tlio scntonco or words or sounds phonetically. 

40 I will now briofly describo some modifications in tho construction and operation 
of tlio phonograph and phonot. 

In Fig. 1G tho indenting point c is upon a spring arm c 2 , ns in Figs. 1 nnd 2, but 
there nro short sections of rubber tubo c 2 at each side of tho diaphragm b to dampen 
the diaphragm nnd prevent fnlso vibrations. 

45 In Fig. 17, the rubber of the diaphragm acts against tho outer end of tho 
arm c- to increnso tho loverngo nnd losscn tho depth of indentations in tho 
foil UIld ld *° W ° P tbo rooord being mado in loss yielding material than tin 

rn P |-"\ 18 s ' lows a modification of tho last-montioncd dovico, tho pressure being 
cl) applied to tlio arm c a between tho indenting point and tho support for tho arm so 
ns to increnso tho depth of tho indentations. 

hig. 19 shows the arm c 2 made as a lover with a spring. 

tig. 20 shows tho indonting point upon the center of a spring bar tlint is firmly 
55 or otllo ° nd ’ tbe bar 13 conucotcd at its conter to the diaphragm 6 by a string 

P;g.-21 represents tlio diaphragm b as of concave form instead of flat. 

il o 1 allows the indenting point upon a spring secured to tho diaphragm. 





8 A.D. 1878.—N° 1644. Bpeotaotioo. 

Edison's Improvements in Recording and Reproducing Sounds. 

Fig. 23 shows a disk upon tho spring o’ of tlio indenting point; this disk is 
piaeod quite eloso to tho diaphragm and is moved by the air as tho diaphragm is 
vibrated, the disk being so close to tho diaphragm that tho two will vibrato 
togother, as air cannot pass botwoen or escape ns rapidly ns the vibrations tako 
plaeo. g 

Fig. 24 shows tlio diaphragm vibrated by electro-magnetism; in this ease tho 
diaphragm is to be of iron, and the power of tho electro-magnet will bo varied by a 
rise and fall of electric current passing through tho helix of tho oleetro-magnet; this 
riso and fall of electric tension is to bo produced by tho action of sound upon a 
diaphragm and conueetions in an electric circuit. Id 

Jjig. 25 shows tho method of vibrating tho indenting spring and point by tho 
direct action of an olectro-magnot without tho use of a diaphragm, the electric 
tension m tho holix boing varied by sou: .a vibrations upon n diaghrngm. 

Fig. 20 shows tho spring arm c ! connected to ono end of a permanent magnot so 
as to highly magnetize tho reproducing point; tho foil should be of iron. Whon 15 
tlio pomt passes an indentation tliero will bo less attraction than whon passing no 
indentation, this will givo good nrticulntion freo from tho scraping noiso of tho 
point on tho foil, for in this case it does not touch tho foil, but is worked bv 
magnetic attraction. 3 

Fig. 27 represents two instruments in connection with the cylinder n; in thisenso °l) 
«io plmnet and the phonograph are separate. Tho phonograph records in the usual 
manner, but the phonet has its diaphragm set in motion by the riso and fall of tho 
f his reduces tho scraping noiso of the foil and acts by lovoram, and a 
point c tenS '° n t0 '" 0V0 tho dia P llrft 2 m “s fcl| e phonogram is moved beneath tho 

nniTw 28 B ' l0 "i' 8 nn arrangement whereby four persons may speak simultaneously 
OTmn will “Pf™ 1 , 0 P arnl,el l; nes upon ono cylinder, and tho phono- 

one voi™ 1 d the sounds the same os though it contained tho record of but 


as ^n'sdin r 1 sln S le p h°uogi'aph adapted to receive tho voices of three persons 30 
or n^ ( l, r°T d3 , made by the tllroe voices are convoyed through flexible 
t, tio s l , f b wl.co '° d,0 J , hragm, and will bo recorded in a single lino of indon- 
tho three voices! repi ' 0duced b F tho P hone t the sounds uttered will correspond to 


■e“ ved This no „ • WayS Lo ,°PP osito the lin ° of perforations ns tho cylindc? is 
evorytimo a ZZnL\ ZT^ K* S ?, UrC ° of ?o'»P*cssed air or other fluid, and 
oylimlerand asound is tiro ) UCS i° 1>p0Slte i tho nozsslo, a puff of air pnsses into tho 40 
be placed on a snrhit htf l ' P °, n tbo ,I’ rinoi P l0 of the siren. The nozzle may 
forations. P g t k ep tbe cnd of the nozzlo in contact with tho line of per- 

diapln'agm andlL^VthTieco ' 1 ’!! - nS - " mde • W , i 1 t ' 1 a oba,nbor botwoon tho 
the person speaking or tho sound e 16 'especially useful in collecting sound when 45 
instrument 5 d to bo rccol ' dod 18 made several foot from tlio 

tho plionogmph! 8 Th^funnol'formh th “. indo , ntin 8 P oinfc , may bo dispensed with in 
at the larger end or monllllLcc , 8 11,0 P hon osraph is made with a diaphragm 
to the foil on tho cylindor o pin a , vel 7, s {“ al1 liolo at tho pointed end adjacont 50 
will be made by tYe direct ’a!,l M,° Uld • b ° ^ thin 60 that tho indentations 
without the interposition of the indenting“pokt™ “ ° 0UC0ntrated ^ tho funno1 
upon an endless bolt'° this'll Tne'' tb ? P[ lono tP» m or sound record has beon modo 
be made to imitate tho bark of °a doc'ijr 1 othar'rf’ 8m0n *' , or , to >' 3 > n8 the same may 55 
K ot a dog or other nomo made by an animal; and this 


BpedfleAUon. A.D. 1878.—N° 1041'. 0 

Edison's Improvements in Recording and Reproducing Sounds. 

belt may bo of stool or otlior hard material that allows tho same to be used for a 
long poriod of time. 

Fig. 34 is a perspective viow showing a double phonet, there boing a spiral lino 
of indentations on onch sido of tho revolving disk d, ono phonet coining into action 
5 ns tho other finishesin this ca-so tho spirals should bo in opposite directions, so 
that tlio disk continuing to revolve in the same direction moves ono phonet from 
tho contor outwards, and then the other phonet is oonnoetod and moved back 
towards tho contor ; this may bo used as a toy. 

Fig. 35 represents a phonet in which the phonogram containing a sentence, 
0 speech, words, or other sound record is upon a bolt or strip wound upon a rcol; 
tins bolt is drawn along gradually and wound upon tho socond roller by any 
suitable moclmnism, and ns tho phonogram is thus moved it actuates tho 
phonet c, b. 

Fig. 30 shows a phonograph or phonet similnr to that shown in Fig. 12, tho 
5 cylinder q is revolved, but remains in ono positson, and the phonograph or phonet 
is movablo back and forth over tho cylinder. In this instanco tho arm mr is 
extended beyond tlio screw Id, and passes beneath the inclined spring guide m 5 , 
when the screw is carrying the arm and phonograph towards tho right; as tho 
arm m" passes from boneath tho end of the guido m s it is no longer hold to tho 
!0 screw, and tho arm m- and phonot are lifted by tho guido m 2 as tho springs m° 


„ . . and arm, along to the place of beginning, at which 
place the arm m- drops oil' tho end of tho inclined guide m 5 into tho thread of tho 
screw, and as this revolves it carries the arm along beneath tho guido m° as 

5 Fig. 37 represents the phonograph or phonet upon a pivoted arm, so that it may 
swing across or at right angles to tho line of movement of the intended material or 
phonogram. In this case the lino of indentations may bo lengthwise of tho bolt, or 
across the same in tho arc of a circlo. 

Fig. 38 shows a phonograph similar to that shown in Fig. 31, except that tho 
0 sound chamber is of a different shape. 

Fig. 39 shows n mouth-piece with an orifice of soft rubber to fit the mouth or tho 
lips of tho person speaking, so that all sound waves will bo confined to the chamber 
and diaphragm. 

F ig. 40 shows tho mouth-picco of tho phonograph made with cross slots with 
5 irregular edges. 

Fig. 41 shows tho mouth-pieco as perforated with numerous holes. 

Fig, 42 shows but one oponing in tho mouth-pieco; tlio edges of thisaro irregular. 
Theso irregular edges roinforco tlio hissing sounds and cause a more perfect phono¬ 
gram to bo produced. 

0 Fig. 43 represents a mouth-pieco of mica with a central opening protected at its 
edges by a wooden ring. 

In Fig. 44, the diaphragm b is of wire gauze with a backing of paper connected 
to it by any suitable cement, and there is a ring of still' papor at tho edges of tho 
flauze disk to strengthen it. 

d Fig. 45 represents a diaphragm b of parchment or similar material strotchcd 
tightly within tho framo 5° by cords and screws. Tho cords may bo of different 
lengths and tension, and respond to and roinforco certain sounds. 

* *B- 40 shows a mouth-pieco for tho phonot mado in imitation of the human 

mouth. 

11 Fig. 47 ioprosents the body portion of tho phonograph or phonet mado triangular, 
and the diaphragm is of corresponding shapo. 

1’ig. 48 represents three cylinders, each provided with a phonograph or phonet; 
111818 useful in recording and reproducing threo-part singing or musio. 

Fig. 40 represents a phonet mado os a tube, with flaring or trumpet-shaped ends, 
a anil with two diaphragms 15, 10, placed crosswiso of tho tube so os to form an air 
chamber. Tlioro is a third diaphragm b, which is vibrated by tho movement of tho 
•reproducing point o, and said diaphragm gives motion to tlio air in the chamber, 


with a central opening protected at il 








10 


Edison’s Improvements in Recording and Reproducing Sounds. 

nnd vibratos tho diaphragms IS, 10, which latter product) air waves, and tho sounds 
issuing from tlio two trumpet-shnpod ends will blond nnd increaso tho volume of 
sound. 

Fig. SO ropresonts a dovioo whereby dcon indentations nro inado in tho motal foil. 
Two dinphragms nro omployed, tho first (6 s ) is vibrated by tho sound vibrations, 5 
and controls a vnlvo 6’ in a tubo connected with a source of compressed air or other 
fluid; this vulvo id allows more or loss air to pnss to tho diaphragm b, according to 
tho vibration of tho diaphragm lr, hence the diaphragm 6 will vibrato in harmony 
with the diaphragm lr, but it will bo noted upon by greator force, nnd consequently 
the indentations will bo deeper in tho foil than if tho dinphrngm b was noted upon 10 
simply by tho sound vibrations of tho voice. 

Figs. 61 and 52 represent n dovico that may bo used with a phonot to increaso 
tho loudness of tho sounds reproduced. Tho sound vibrations from tho phonet nro 
conducted by a tubo shown by dotted lines in Fig. 51, to tho dinphrngm 6 s that 
controls a valve V in a tube connected with a reservoir of air or other fluid under 15 
pressure, and tho nir ns it escapes by tho vnlvo passes into tho trumpet-shaped end 
of the tubo, nnd produces sounds that nro very loud nnd clear, and nro a repro¬ 
duction of tho sounds resulting from the uso of ono of tho phonets beforo described. 

This same apparatus may bo usod to reproduce with louder utterances a person’s 
voice, tlio the sound from tho voico being used to vibrato tho dinphrngm b\ and 20 
thereby rcgulato tho nir waves escaping from tho valvo IP into the trumpet. 

Fig. 53 shows the speaker’s head within a box or enso; in this instance nearly all 
the sound vibrations act upon tho diaphragm. 

Figs. 5 t nnd 55 illustrate how tho movements of tho lips in speakin" may bo 
recorded and reproduced In this instance, a lover applied to tho diaphragm carries 25 
the indenting point c, Fig. 55, and tho end of this lever is placed in the mouth of 
tho speaker, and tho movomont of tho lips regulates tho indontationB in tho foil. 

A similar apparatus shown in Fig. 54 within n case is connected to tlio movnblo 
lips ot a mask, so that theso lips open nnd closo as in articulation, at the •same time 
that the sound vibrations are given by tho phonogram to tho plionot. 30 

'ig. jo represents a toy phonot in which tho phonogram strip 35 is secured at 
Zi 7 ” T upon which it is wound. By pulling upoii tho strip it is 
unwound, and a rubber cord 37 is wound upon tho shaft of tho cylinder. When 
win H re 7 VCd fr0m the lndented Btri P' tho rubbor oord rotates tho shaft and 
w nds up tlio phonogram upon tho cylinder, and tho sounds are reproduced in tho 35 
tl m slmftin 0 I )lono S™ m nctmg upon a point and diaphragm a. Tlio movement of 
■tlio shaft is regulated by tlio fan, worm, and pinion 38. 

with urns timin' ?5 dlDdor f°r moving tho phonogram strip is shown as provided 
along vciy^rogular. 61 h ° leS " Uw ^ ° f stri P ’ “ «•. strip l bo fed ^ 

fo/the itrip 8 ' th ° ° ylind0r With pi " S is 8llown as nmde with heads to act as guides 

ind F cLfons OW TllL°‘ !nd f tiDg u ev!c0 for amplifying or increasing tho size of the 
a 3 nnd tliora is n 1°™*° ^'n° r .° 7' one of which a 4 travels fastor than tho other 
cylinder Ono nnint Ml 4 ° I? lv< ? to . d at , 41 > “ nd provided with a point o for each 45 
upon a 4 and as this * f ° dowi i, tb V ndentnt,lons 4n tbo cylinder a 3 , and tho other rests 
and al o dconor e‘ IS ,, trave ! a , tbo f a3tcst > indentations made therein will bo longer 
In Fie GO one P ?i nt , b 7 e nt . tb ? outor ond of tho >«vor. 
record in relief Tlii«°L 4 tb ?J )air , 18 mado of Pardoned motnl with tho sound 
m other motal t d^" “ n? n - V 7=7^° " °«><* process from an iron foil 50 

arrangod\o m to knurl or iml,if^ ff bardenod motal with tho record in relief, nnd 

Wtasrat’sa--——. 


gpcclflcatlon. 


11 


A.D. 1878.—N° 1614. 


Edison's Improvements in Recording and Reproducing Sounds. 

tho cylinder and mold with plaster of Paris orothor suitable material. Tho mold is 
of metal with a screw or spiral rib projecting therefrom, and it is mado in two parts 
nnd hinged so that it can easily be removed when the plastor of Paris is dry, 

For amusement or instruction, the phonograph is capable of extended uso; for 
5 instnneo, a revolving cylinder, soo Fig. G3, containing rows of indentations repre¬ 
senting tho letters of tho nlphabct, and provided with koys containing corresponding 
loiters can bo usod in teaching tho alnhabot, and sentences, speeches, nnd other 
matter can bo spoken by tho plionot, and repeated by tho learner without tlio oyo- 
sight being called into uso. 

10 Clocks may bo provided with phonogram cylinders or wheels to call off tho hours, 
to givo alarms, &c. ~ , „ 

The phonogram may bo upon a strip, sheet, belt, or roller, and it can bo of a 
dog’s bark, a rooster’s crow, a bird’s song, a horse’s neigh, and theso can bo used in 
toy animals with a simple phonet for reproducing tho sound. 

15 In copying phonograms, or making duplicates, an original phonogram may 
receive a deposit of copper or iron in a plating bath ; and, if of iron, may lie car¬ 
bonized to convert it into steel and hardened, and then the same should bo backed 
up with typo motal, and used for impressing strips or pieces of motal. 

A bed of gutta pcrclia, or similar material, may bo used to sustain tho sheet 
20 motal while being pressed. Numerous copies of tlio original phonogram can thus bo 
reproduced. 

A plaster cost can bo used for producing a copy by pressure. 

The governor to rc'ukto tbo speed of tlio instrument may bo made of a pen¬ 
dulum wei'dit Gl, see Fig. G4, hung at tho lower end of a rod that is provided 
05 with a universal joint at G2, and tho upper end of tho rod is moved around by a 
crank G3 that is revolved by tbo train of gearing. As tho speed increases tbo 
weight will describe a circle of larger diameter, and thereby increaso tho 
resistance. . . 

Tlio universal joint maybe displaced by a spring wire, big. Go, that allows ot 
30 tho movement. , , ,, 

A magnet G4 upon tbo crank arm G3, Fig. CG, may bo used to revolve the pen¬ 
dulum by attracting an armature at the upper end of tho pendulum rod, and 
thereby avoid the friction resulting from the contact of the surfaces of the pendulum 
rod with the crank. ’ . . .. 

35 In Fig. G7 the diaphragm b is represented as connected to a pair of delicate 
piston valves within a tubo 08 that has three ports; ono, Gl), is connected to a 
reservoir of compressed air, the others, 70 and 71, are connected to a chamber {2 
at opposite sides of a diaphragm, so as to vibrato tho s.amo in harmony with tho 
diaphragm b, but tliorc will be greater amplitude given to tho same by the pressure 
40 of the air, and by a connection to tho phonet diaphragm V tho sound producod will 
bo greatly increased. 

Wlmt I claim os my Invention is,— . . . - 

First. The combination with tho diaphragm and point of a flat lccoivmg surlncu 
and means for revolving the receiving surfaco, and causing tho point to follow 
45 a voluto or spiral lino, substantially as represented in Figs. 1, 2, C, 7, 8, 9, 10, 
ami 34. .■ » . 

Second. Tho combination with the revolving plato phonograph or plionut ol n 
propelling weight or spring and a governor to rcgulato tho speod, and ensure uni¬ 
formity of movement, substantially ns set forth. , „ 

60 Third. A revolving disk provided with a clamping frame to secure tlio foil or 
other material in combination with tho swinging arm, diaphragm, and point, sub¬ 
stantially as specified. , , , , ,, , 

Fourth. In a phonograph or phonot, a spring introduced botween tlio diaphragm 
nnd tho point, substantially as set forth nnd shown in Figs. 1G, 17, 18,19, 22, 
55 nnd 2G. 

Fifth. In a phonograph or phonet a rubber spring, or similar dovico, to dampen 








12 A.D. 1878.—N° 1044, ww. 

Edison's Improvements in Recording and Reproducing Sounds. 

tho vibration of tho diaphragm, nnd provont falso vibrations, ns set forth and shown 
in Figs. XC nnd 21. 

Sixth. Tho combination with tho diaphragm in n phonograph or phonet apparatus 
of a lover to modify tho relative notion of tho diaphragm and point, substnntinllv 
ns described, and shown in Figs. 17,18, 27. * 

Seventh. Tho combination with tho dinphrngm nnd point of a pormnnent or electro¬ 
magnet, substantially as describod, and represented in Figs. 24, 26, 20. 

. Eighth. The method of recording and reproducing two or moro sounds or Bpeoches 
-ultanoously, substantially ns describod, and ns illustrated by Figs. 28, 20, 

Ninth. A phonet composed of n perforated sirene nnd a jet tubo, substnntinllv ns 
described, and represented in Fig. 30. 

Tonth. Tho mechanism for producing n phonogram, nnd employing tho snino in a 
phonet, substantially ns described, and illustrated in Figs. 32, 33, 35 30 nnd 37 
Eleventh. The combination with tho phonograph, diaphragm, nnd’ point of a 1 
nnd53°somber, substantially as described, and illustrated in Figs. 31, 38, 39, 

delwibml^n l dinp -n rn8 » lu , an , d . m ° l ! th -P iecos speaking phonograph, substantially 
as desenbod, and ns illustrated m Figs. 41, 42, 4.3, 41, 45, nnd 40. 

6ntb ' Th ° c , ombination witl ' a diaphragm nnd its point of two diaphragms 2 
for the purposes, nnd substantially ns shown in Fig. 49. ! ° 

viStan!! nth ' Th ° °° mbiDation with a diaphragm and valvo nctuntod by sound 
vibrations a source of compressed fluid and a trumpet, os in Figs 51 5“> or a 
phonograph ns in Fig. 60, substantially ns set forth. & ' ’ 0r ft 

Fifteenth. The combination of two diaphragm*! with a valve and a sour™ of 0 
o“XTs e ound m n; “ *** ° 7 ' for in0l0a9i "e «» volume of the voice “ 

soil^ 

->—« vt— - **» 

hand^nd Teal,* thL 17th °day of^Sep^^bw^ A.D ^^ my * 

Witnesses, THOMAS ALVA EDISON. (l.s.) 

Cha 8 . H, Surra, 

n _ 7G ‘ Cliambers St,, Now York, ,. 

HABOLD Sebhell, 70, Chambers St., Now York. 45 

LONDON: Printed by Okoiiok Eim*Ann Fviiu •». i w „ " 

For Her* Mfycsty’u Stntionety Office, 



























































A.D. 1878, IBth June. 


Telephones and Apparatus Employed in Electric Circuits. 


LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in tiio State of Non 
Jersoy, United Stntes of America, for the Invention of “ Improvements in 
Telephones and Apparatus employed in Electric Circuits." 


PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at tlio 
Ollicc of the Commissioners of Patents on tlio loth Juno 18/8. 

Thomas Alva Edison, of Menlo Park, in tlio Stato of Now Jersey, United 
States of America. " Improvements in Telephones and Apparatus employed 
5 in Electric Circuits." 

In this apparatus I mako use of a pinto or body against which tho sound waves 
in the ntmosphero act, and connected therewith is a button or buttons of carbon or 
other semi-conducting material placed in tho electric circuit. Tho pressure duo to 
tho impact of the sound waves acts on tho carbon, and produces tho rise and fnl. of 
10 electric tension in tho circuit. 

The circuits are nrrnnged to bring into action one or more primary and secondary 
currents, and an reduction coil or coils, and switches and a call, so that signals can 
bo sent and messages transmitted in opposite directions over ono lino. The receiving 
instrument is provided with an oicctro-nmgnot and an armature formed of on iron 
15 plate diaphragm, and a hammer is attracted or repelled so os to strike upon the 
diaphragm to form a call, and a stand is used to keop the telephone instruments in 
premer position for tho call to act. ... , , 

Two or more vibrating instruments connected in tho same circuit, and operated 
by electro-magnets are thrown out of tho circuit by a shunt, and act to give 
20 “goals in two distant instruments provided with diaphragms. I employ a. con¬ 
denser in tho local or main line circuit to neutralize tho static charge or discharge, 
Which condenser is preferably made of two strips of foil wound into a spiral form, 
with non-conduoting material intervening, and to which strips the respective 
circuit wires are connected. , , , , 

25 The carbon employed in tho circuit is proforably tho finest quality of selected 
lamp-black, consolidated by heavy pressure, but plumbago and various forms of 
carbon or iodide of copper, black oxide of manganese, finely divided metals, 
[Price 10d.] 













































Edison's Impls. in Telephones and Apparatus Employed in Eleelrio Circuits. 

poroxido of loud, or similar semi-conducting materials reduced to a powdor and 
moulded in buttons or discs may bo employed. 

The induction coils servo to throw into the lino a powerful induced curront, and, 
in some instances, I employ a battery connected with the lino, and balanced so that 
the sound waves noting on tho carbon or other resistance, cause oither the positivo 5 
or negativo of tho battery to preponderate on tho lino. The condenser introduced 
in the same circuit gives both static and induction currants. Fine wires may take 
tho place of tho strips of foil in the condensers. 

Where tho air waves strike upon a vibrating plato or disc, tho chnngo of pressuro 
upon tho carbon may be obtained from a thin strata of air intervening between the 10 
diaphragm and the platina plato of tho carbon. 

A nmgncto-eloctric rancliino is sometimes used ns the soureo of electric energy in 
place of a battery, and tho telephone instrument placed in tho Wheatstone bridge, 
and place resistances to balance the electric forces, so that variation of tho resistance 
in the telephone sends tho current on tho lino. 15 

telephones in local circuits or shunts at wny stations, with induction coils in tho 
mal ° lino, are used for operating local telephones on tho main lino. 

. *be sound vibrations act by leverage upon the carbon or other resistance, to 
increase or lessen the motion ns circumstances require. 

A secondary battery in somo cases is employed in place of a condonsor, and a 20 
thermal battery can bo omployod as the source of electric energy. 

\\ here the electric curront is made to pass through water or an electrolytic 
solution, the diaphragm acts upon a valve or cut-off to vary tho volume of liquid 
whero tho current passes, and effect a rise and fall of electric tension. 

A Uuluco dry pile is combined with a diaphragm at each terminal for transmitting 25 
and receiving sound. 

An olectropliorous similarly combined is sometimes employed for tho same 
purpose. A ¥ 

Calls are combined with tho telephono so as to attract attention to tho 
instrument. gQ 

These calls are operated by pendulums, forks, or reeds, which set up magneto-' 
electric currents when vibrated, and from these tho boll or other cull receives its 
movement iroui the distant station. 

il r . e< : eivi "E portions of tho telephone aro of a character adapted to respond to 
the electric pulsations from the transmitting telephones aforesaid. 35 

~ 1 “ 0 there are two or more receiving diaphragms to one air chamber to 
augment tho sound. 

i\rili i , l ,!!! 1 ° r i"! lt i*' 0 USe a - d. am P er u P on the diaphragm to prevent falso vibrations. 
omnloveiW 8 “ recolvlll g motion from tho electric action aro sometimes 

the receiving diaphragm, and tho magnet of tho receiving 40 
diaphragm is polarized with a local battery and double coils. 

electric'!„ gm “needed directly u P on the induction coil will respond to tho 

electric waves and give audible sounds. 

joints anTproforaWo 19 Wir ° S ^ ^ telepllone conne ctions, wires with universal 
sound, S funnels are uset * the tolophonio receiver to increase the volume of 
ture ll orTv^ 6 mm!p r n COn r^ 0t ' 0n ° f 8nsCB an< * °** lor mat erials by change of tempera- 

m ’ a, ° 

Induction coi?s lire‘miido of V f Un ^ or > 1 )lacc(1 in * Wheatstone bridge, 

and the condense™ nv, °5 f ° lms speomlI y adapted to tho telephone apparatus, 
a tno condense!s are sometimes connected in a continuous metallic circuit 55 


Edison's Impts, in Telephones and Apparatus Employed in Electric Circuits. 

SPECIFICATION in pursuance of the conditions of tho Letters Patent filed 
by tho said Thomas Alva Edison in the Groat Seal Patent OMco on tho 
13th December 1878. 

Thomas Ai.va Edison, of Menlo Park, in tho State of Now Jorsoy, United 
5 States of America. “ Improvements in Telephones and Apparatus employed 
ix Electric Circuits.” 

In this apparatus I make use of a plate or body against which tho sound waves 
in tho atmosphere act, and connected therewith is a button or buttons of carbon or 
other semi-conducting mntorinl placed in tho electric circuit. Tho pressuro due to 
[0 tho impact of the sound waves acts on tho carbon, and produces tho riso and fall of 
electric tension in tho circuit. 

Fig. 1 is a vertical section of tho transmitting instrument, and Fig. 2 is a plan of 
n portion of tho same. 

The body of tho instrument is made of the two shells a and h, between which 
[5 the diaphragm c is clamped at its edge, and said diaphragm recoives the impnet of 
tlio sound waves which enter through the opening or moutli-pieco 6'. c is a disk of 
insulating mnterial secured to tho screw/, and in a cavity in this disk is tho carbon 
button h botweon tho platina disks 1 nnd 2 ; tho disk 2 is secured to tho scrow /, 
and tho disk 1 is connected to tho metallic ring 3 by a strip of platina at 4, in 
i0 order that said disk 1 may bo free to move. 

Tho disk 1 is connected to the wire 5, and the disk 2 to tho wire G. 

Upon tho dinphrngm c there is a short tube i that rests upon tho disk 1. As 
said diaphragm receives tho impact of tho sound waves, tho carbon button is sub¬ 
jected to different pressures, and varies tho resistance to the passago of tho electric 
15 curront through the same, consequently, tho current passing in tho circuit is varied 
in its electric tension; this current acts in tho distant receiver ns hereafter ex¬ 
plained, to givo movement to a diaphragm, and produco sounds corresponding to 
those which are received upon the diaphragm c. Tho screw / allows of the carbon 
button and disks 1 and 2 being raised or lowered to adjust tho initial pressuro of 
10 the dinphrngm on tho carbon button. 

Tho carbon employed for tho button A is preferably tho finest kind of selected 
lamp-black consolidated by lienvy pressure, but plumbago, carburet of iron, gas 
retort carbon, or various compounds which aro partial conductors in the dry stnto 
may be used, such as iodide of copper, black oxido of manganese, peroxide of lead, 
15 or similar scini-condiicting materials, reduced to powdor and moulded in buttons or 
disks ; also finely divided metals, such as platinum, black gold, or disks of metal 
with n roughened surface having many points may bo used. The circuits are 
arranged to bring into action ono or more primary and secondary currents, and an 
induction coil or coils, and switches, and n call, so that signals can be sent and 
10 messages transmitted in opposito directions over ono lino, as illustrated in tho 
diagram Fig. 3. . 

A at station 1 is tho carbon transmitter, and said instrument is included within 
the primary circuit of the induction coil D, E. D is tho primary wiro of tho coil, 
and is wound on tho outsido of the secondary coil E. 0 is a switch, which, when 
15 moved to the right in contact with 15, places tho transmitter A in tho primary 
circuit containing tho battery It nnd coil D. When tho switch is in tho center the 
primary circuit is open, and tho apparatus is ready for tho reception of a call 
signal. 

When the switch is turned to tho left at 1G tho instrument A is thrown out of 
in circuit, and tho battery only is connected to tho primnry coilD. Tho movoment of 
tho switch from 1G soveral times sorves to open nnd closo tho primary circuit, and 
throw a powerful induced current into K, and then to tho lino. The polarized 
relay p, coil nn( j reC eiving instrument B, aro nil placed in tho main line wire at 
both stations. The poworful current thrown into tho secondary coil and line by 
>5 tho movement of tho switch C from 1G works the tongues of both polarized relays 1< 








Edison's Impts, in Telephones and Apparatus Employed in Electric Circuits. 

in unison with tlio switch, tho tongues closing against tlioir contact points close a 
local circuit containing a call hell H. 

Ths same battery K that is omploycd with tlio telephones is utilized to ring tho 
bell. Tho connections for tho transmitter A arc from tho battery K by wire 20 
to 21, then through tho telephone A to wire 22, and from 22 to 15, through tho 5 
switch lover C to tho primary coil 1), nnd to wire 23, back to battory. This is 
the connection for transmitting and receiving tclophonically. When not thus 
working the switch C is placed in the central position between 15 and 1G. When 
in this position, if tho switch of tho distant station is moved to operate tlio call, 
tho tongue of F closes tho local circuit at g, thenco by wiro 21 to battery K, and 10 
through K to wiro 25, thenco through tho magnets of tho bell call to wiro 20, nnd 
then through tho tonguo of the polarised relay. When tho switch C is moved to 
work the distant call it is brought into contact with 1G, and tho current passes 
from K by wiro 20 to 10, thenco through C to tho primary wiro D, thenco to 23, 
back to tho battery K, nnd sotting up a powerful induced curront in tho coil E and |J 
line. I will mention that it is not necessary to use a polarized relay, ns an 
unpolnrizcd relay of tlio ordinary character may bo used as tho current duo to tho 
opening of the primary circuit is much tho strongest, but tho lover of the unpolnrized 
relay should bo light nnd tho spools very short. It is not even necessary to uso 
the call bell H in many instances when the terminal is very quiet, ns tho sound 20 
given by the polarized relay itself is sufficient, or a small bell may bo worked by the 
tonguo of tho relay itself. The tongue of tho polarized relay should bo biased, so 
that it will always be away from the point g, except when moved by tho signalling 
currents, so as to prevent short circuiting tho battery K when transmitting 
telephonically. By employing two cells and a considerable resistance in tho magnets 25 
upon the call bi-11, it is not essential to bias tho tonguo, but it may bo mndo to 
respond to both positive nnd negative, a shunt from one cell being used to furnish 
current to tho call bell. The receiving instrument is provided with an electro¬ 
magnet, and an armnturo formed of an iron plato diaphragm, and a hnmmcr is 
attracted or repelled, so ns to strike upon tho diaphragm to form a call, and a Btand 30 
is used to keep tho telephone instruments in proper position for tho call to act; 
these devices are shown in Fig. 4. A is tho receiving instrument, provided with a 
diaphragm and a magnet for giving motion to it, tile same as shown in British 
Letters Patent No. 2909, of 1877, granted to me. Tho magnet of tho receiving 
instrument is included in tho main lino a, a, a; C is tho primary coil; D, the 35 
secondary coil, which latter is included in the main line circuit; e is tho soundor 
lever resting upon the diaphragm of A ; X is a rack or stand for holding both tho 
receiving and transmitting instruments when not in use. S is a switch; when it 
“ .^ u ™ ecl l ,° , tlle P oiut the transmitter B is included in tho primary circuit with 
con O nnd battery Q, and tho transmitter serves to increuso and dccreaso its 40 
resistance when the diaphragm is vibrated by sound. 

The transmitter is provided with a carbon button, through which tho current 
passes, and it produces more or less resistance, according to the strength of the 
sound waves impinging on tho diaphragm, as beforo described. When tlio switch 
lover S is moved to the point 2 the secondary wiro of tho coil is short circuited; 45 
it remains in this position for the recoption of a call signal from the distant station; 
were the coil D loft in circuit it would tend to weaken tho signal call by its 
re„iotanco to the passngo of the curront from the distant station. When tho switch 
Jovor is at tlio point 3, the curront from the battory Q passes only through tho 

“meeting nnd disconnecting tlio switch S from tho button 3 50 
* m l uotl ? n waves are thrown into tlio lino, and act upon tho distant 
receiver to attract and repoU the lover c, and give tho signal call. Tlio induction 
coil C, D, may bo made as in Firr. r. 1_ n c _u_ 


th ° ? no wire D wound around tho same forms tho secondly coil, tlio latter 
explained ” 4mam olromt ' and tho formo F in the local circuit, as heretofore 55 
Two or more vibrating instruments connected in tho same circuit nnd operated 


llwltt , llon . A.D. 1878.—N° 2390. 8 

Edison’s Impts. in Telephones and Apparatus Employed in Electric Circuits. 

bv cloctro-mngnots aro thrown out of tlio circuit by a shunt, and act to give signals 
in two distnnt instruments providod with diaphragms. This arrangement is shown 
in Fig. 6, in which tho connections at ono oud of tho lino aro represented. Fig. 7 
is a section of the resonant tubo. 

5 F and O are tlio vibrating reeds kopt in continuous vibration by the electro- 
iiiu'-ncts K and S in a local circuit, provided with a suitable contact spring operated 
liyllio rood in the usual mannur, but which aro not shown hero for clearness. 

J[ and N are electrolytic cells arranged and operated similar to those shown in 
aforesaid Patent. No. 2909, The armatures of the electro-magnets are harmonic 
10 reeds. The vibration of one of tho electrodes serves to increase and decrease the 
resistance of tho electric current by causing tho current to pass through a greater 
or less amount of water between the electrodes. L is tho main battery in tho main, 
lino T, in which are the cells M, N. II and Iv aro keys used for the purpose of 
stopping nnd starling tho waves over the wire, which they accomplish by short 
15 circuiting tho electrolytic cells N or M. The reeds F and G aro tuned to give 
different tones and several reeds, substantially the sntnu as herein described, may 
be included in the same circuit, all being toned differently. A and B are the 
receivers which are shown as resonant tubes. Upon the ends of tlio resonant tubes 
are iron or steel diaphragms, which act ns tho armatures of tho electro-magnets 
20 E E 1 , which are facing them. X and X 1 aro secondary tubes which slide within 
the tubes A & B like tho tubes of a tclcscnpo. The objoct of tho tubes is to allow 
of tho lengthening or shortening of the column of air in tho resonant tube, so as to 
bring it in unison to the particular note or tone which it is desired to hear. The 
iron diaphragm responds to all the tones with equal power, and were not some 
25 means provided for strengthening or reinforcing ono particular tone it would bo 
very difficult for tho operator to pick out tho tone required, but by the uso ot the 
resonant tubes this difficulty is ovorcome, becauso tho tone is given distinct when 
the armature is vibrated in harmony with tho noto of tho tube. 

Tlio induction coils servo to throw into the lino a powerful induced current, and 
30 ill some instances I employ a battery connected with tho line, and balanced so that 
the sound waves acting on the carbon or other resistance cause either tlio positive 
or negative of the battery to preponderate on tho line. The induction coils and 
their arrangement in tho electric circuits aro shown in Figs. 9, 10,11, and 12. In 
Fig. 9 tlio transmitter is provided with tho diaphragm c and carbon button A, as 
35 beroro described 1, 2, and 3 aro induction coils having their primary cods wound 
on the outsido, and all connected in the same circuit, in which also is included the 
disks 1, 2, carbon button h, and local buttery B. Tim secondary or inner coi s o 
1, 2, nnd 3 are nil connected together and are included m tho mam lino circuit wun 
tlio receiver and call boll. The impact of tho sound waves upon the diaphragm c 
40 subjects the carbon button to moro or less pressure according to their strength, 
hence the resistance of the circuit will be varied owing to the small resistance of 
the local circuit and tho power of tho battery; a very slight change in the 
resistance of the circuit throws a powerful induction current into tlio secondary 
coils, which passing over tho lino sets tho distnnt receiver in vibration corre- 
45 spending to tho air vibrations striking the diaphragm of tho transmitter, 
object of using moro than ono induction coil is to get a greater amount of wi 
nearer tho iron cores, which are bundles of iron wire. In Fig. 10 the same kinds 
of coils are shown, but they are connected in the local circuit shghtly diffoiont^ 
being connected in derived circuits, or for quantity. In Fig. 11, but one eecondary 
M coil is used, tho primary circuit being divided into several coil?, arranged for 
quantity. This brings more current from tho battory and a very slight change in 
the resistance in the carbon button of tho transmitter causes a power! 1 nd cid 
curront to circulate in tho secondary coil nnd line. In Fig. 12 is shown Mother 
method of arranging tho local batteries so that when the diaphragm of the 
55 transmitter is in its normal position its resistance is equal to R when no current 
passes in tho primary coil of the inductorium, but tho shghtest change in the 
resistance of the carbon button h destroys tho balanco between the batteries, and a 








Edison'a Impts. in Telephones and Apparatus Employed in Electric Circuits. 

current pusses to tho primary. In Fig. 8, a condensing induction coil is shown 
Tiie coil 1 is formed of two Jong strips of metallic foil presenting n largo surfneo 
to each other; the strips arc wound into a spiral with non-conducting material 
intervening, and to these strips the respective circuit wires nro conncetod. The 
curicnt passes from end to end. One coil of foil is connected in the main lino 5 
circuit and forms part of it, whilo the other is connected in the local circuit 
with the battery and carbon transmitter. Tho induction coils and circuits aro 
sometimes arranged as in Fig. 33, 

At station A the transmitter A is provided with the carbon button and disks 
afore-mentioned. B is the receiver, provided with an iron diaphragm opposito tho 10 
cores of an electro-magnet, the saino as in aforesaid letters Patent, but an ear 
tube at the end of a flexible tubo connected to tho body of tho recoiver is shown 
nt .. 1 • Tbo . transmitter A is included within the primary circuit of an induction 
coil G. C is n switch which when moved to the right in contact with D plnces 
transmitter A m snid primary circuit containing battery F and coil G. It also 15 
allows the line current to pass through recoiver B, secondary coil II, switcli point C 
and transmitter A to ground. When the switch is placed to the left in contact 
with 1 the instrument A is not in circuit, and tho receiver B and coil II nro short 
circuited, so that the lino is completed through the calling sounder J, switch point E, 
primary coil G, battery F, to tho ground. oq 

The batteries are so arranged at each end of tho lino that wlion both switches are " 
placed to left on E they will act together instead of against each other, there being 
sufficient battery to work the calling sounders at each end of the line. At station B 
tiie calling sounder is replaced by a relay J'; this device I use when the lino is too 
ong for the sounder to operate distinctly, or when the call bell K, which is worked 25 

iW.Cnnt. 0f -n ^ nV- re , qlm ', ed to , lje l >!nced nt 11 distance from tho other 
Iiiptiumcnts. file bell Is. is placed in a local circuit witli battery L 
Sometimes I employ a buttery connected with tho line and balanced so that the 
=Z^, nC ,n H °" , t ie Cnrb °, n 0r other '“'Stance cause either tiie positive or 
Zldi. I *?. l )re P™deniteon the line. In Fig. 14 the polaHty of the 30 
i o co.e oi the induction coil D, E, is reversed at every vibration of tiio 

r* W0 C , nrb0 ? button V nd tho di8ks 1 and 2 connected 
with th. batteries B, B and primary coil D. When tho diaphragm o moves 

“ n '- dwb “ 5t «- backward h sends a 

unc^the carbon “‘'u “'"i? vibra f in S P^te or disk the change of pressure 
a ,"! ' . b n ( " ny , ° bt ", In l ° d a tbin strata of nir intervening between the 
the rarbon lmtt he ? , tho c,lvbon ' -%■ 15 "hows a transmitter and 

the an bon button A and disks 1, 2, arranged so that tho pressure on the enrhon is 

L^Xagm m t vibrated me ‘ lt ° f tb ° “ ir between tho diapliragm c and disk 1 ns said 40 

nhme'of a n imt'tl 0Ctri ° wf 1 '" 0 ,’ 9 fnotimes used as tho source of electric energy in 
and rf istanoe» ^ d i tbo telephone instrument placed in tho Wheatstone bridge 

the^hril^e^^ d alS ° Sh0WSth ° Cir ° uit — P ctionswith 

secured aured^'cf T? tru,n ° nt t( V. ns tho mouth-pieco b and a diaphragm e 
tho button h ofra;b n n 1U irf ntr0 , 0 , he v d V , I ,llra e m is platinized, and upon this rests 
the rod a”d surin„ «\ J bo . ,neUll, o di, k 2 is kept in contact with the button by 50 
plate 2 unon the au’h'mJ'f h ' 3 ? n nd J“ot'ng screw to regulate tho pressure of tho 
that is secured to t in ? S,lld scrw P ttasc9 through the metallic support 

nected to the wire 4 ™ T* 6 TF i nrou " d tbo button - ' rh ° diaphragm is* Jen¬ 
neting o„ the Zhraum c nrocSt 2 t0 - tbo Any atmospheric vibrations 

similar button h in the electi-inld B0 a ™ rlftt,lon ln 4,10 resistance of tho carbon or 65 
upon such carbontnttai T ““"“lU'" 1 * "f Hie difference in pressure 

i eu.cn carbon button, resulting from the momentum of the parts and the inertia j 


Edison's Impts. in Tele phones and Apparatus Employed in Electric Circuits. 

of tho plate d. Tho transmitter is in one branch of tho Wheatstone bridge ; II s is 
a resistance equal to that of A when not subjected to sonorous vibrations; It 1 , B-, 
form the other sides of tho balance, and liavo equnl resistances. Tho bridge wire 
from M to N is contained in the telegraphic circuit that extends from N by the 
5 line wire to the distant receiver H, thence to the earth, and returning to tho earth 
plate at tho distant station and to M. The battery B of several cells is between 5 
and R 1 , R s . When the resistance of A, IV, is equal to that of R 5 , IV, no current 
circulates upon the line. Wlion sonorous vibrations vary tho resistance of the carbon 
button h in A tbo current will pass upon tho line in ono direction or tho other. 

10 When the resistance of A is increased tho current passes in ono direction. \\ lien it 
is lessened tho current passes in tiie other direction in consequence of tho bnlnnco 

bt Tho^inih lotion coil H has its secondary coil included in the line circuit, and the 
primary coil is connected with a transmitting instrument T consti noted and 
15 operating in a similar manner to the transmitter A, the bad battery B being in 
tho circuit through the carbon button and primary coil. The receiving instrument L 
is provided with a diaphragm that is acted upon by the core of the induction coil 1J, 
and hence the induction ceil is utilized and serves ior receiving or transmitting 
tclcphoiiically. In Fig. 17 tho balance of the similar batteries 13, B , with opposito 
20 poles to line is obtained by tho rheostat IV that is or a resistance equal to that of 
the instrument A when at rest, and when the resistance ol tho carbon button in A 
iB increased or decreased by tbo sonorous vibrations the current will pass upon tho 
line either positive or negative, according to the resistance in A. In rig. lo a 
modification* of tho transmitter is shown. Tho plate c rests against a disk ot 
25 fibrous substance c\ such as silk, with a finely divided material such as plumbago 
worked into its fibers. There may bo several such disks, and the plate L is at 
tiie opposite side of these disks. There aro edges that are turned over to recoivo 
tiie edges of the mouth-piece b, and a spring c presses the plate c towards tiie 

disks ol' silk so as to hold them against 2. One conductor I... an .induction 

30 coil passes to 2 and tin* other to c, and the slightest sonorous wav us acting 
against c varies tho resistance according to the pressure upon the fibrous.material. 

Telephones in local circuits or shunts at way stations with induction coils in the 
main lino are used for operating local telephones on the mum line, as shown m 

35 F 'VVaml B 5 aro magnets placed at way stations; A', A 5 are carbon transmitters 
which serve to short circuit the magnets more or less, according to the vibrations ot 
tbo diaphragms of said transmitters. . , 

The sound vibrations act by lovernge upon tbo carbon or other resistance to 
increase or lessen the motion as circumstances require. I" *• >g- 20 110 cai on t is 
40 acted upon by tho lover X upon the fulcrum x, and said button is placed between 
tho fulcrum of said lover and tho point whore the lever is acted upon by tho dia¬ 
phragm of the transmitter. In Fig. 21 tho carbon button is acted upon by tho outer 

In Fig.°22 V tbo^arbon button li is secured to the outer end of tho lever X, and 
45 said button rests upon a button of carbon m 1 secured to tho diaphragm c ot tho 

tr TlieW is weighted at a 4 , and there is a spring at a» and adjusting red by which 
the initial pressure of tho carbon button A upon the bu ton a:'may bo ad listed. 
There is a plate A» of mica or other light material secured to tho lever X and upon 
50 this plate the sound waves strike. Tho transmitter is shown as upon a resonant 
box c with an opening in tho toil of tbo box immediately beneath tho dmphrn m c. 
The slightest vibration or jar given to tho apparatus, such as that resulting train 
walking about a room, or front the articulate speech or sound vibrations, vary the 
pressure of A and upon each other, and in so doing tho dcctric conditioni o a 
55 circuit passing through X, A, as 1 , nnd c, and wires 7 and 8 is varied, and cor 
"ponding responso occurs in a distant receiving telephone. 

A secondary battery is sometimes omployed in place of condensor, ns in lig. ii, 








A.D. 1878.—N° 2396. 



Edison's Impts. in Telephones and Apparatus E mployed in Elcctrio CirouitsT 

this is used with ft AVftlloston electrode. This arrangement allows the first part of 
n. we to be strong, followed by n weakening, duo to resistance placed in circuit by 
polarisation of the small point. This extra resistance allows moro current to n Z 
to secondary cod. A thermal battery similar to that shown in my Letters Patent 
aforesaid may be used as the source of electric energy 
When the electric current is made to pass through water or an electrolytic solution 
the diaphragm nets upon a valve or cut-off to vary the vohimo of liquid where he 

current passes, and eflect a rise and fall of olectric tor.sion . 1 

24 ! S £ V0 ^° nl lon e ltudinn . 1 sectio " of o transmitter fitted with this improve¬ 
ment ; and Fig. 2o is a cross section at the lino x, x. 1 

B is a cylinder of insulating material divided by a partition b> into two com- 
partinonts or cell, filled with a conducting fluid. In each cell is an electrode of 
, atina, carbon, or other conductor, one of which is connected to the line wire and 
the other to the battery and earth. The top portion of the partition b' is slb’ditly 

throng tlnTsmall aperture at 2 =0 

t^and^n’Zte^'^ “' C ^ b « ‘ 3 -uUd the dn- “° 

it, and through the slot in'tlio cu", c on'Z hilT^e c!db“ 

decreased in size at every vibration thus inereasiL 1 m.^r 80 '™ 7 '? lncre . ased and 
the passsage of the current from one cell' to tl n° d dt ‘ creasm g tho resistance to 
size of the liquid conductor. If thS amplitude of th °'H t0 t,,0 . alt “ ati ° a in th » 30 
space is nearly, if not altogether dosed a le r tbe dla l ,b,a S''> » very great, the 
its fullest extcAt by the backward ?heTnTtudo a " d t0 

slight increase and decrease in size of the ai ei tnl L I , n,n P lltudo > 3 small only a 
of the opening, so there will bo ?' 0 ' ,lace - “cording to the size 

through tlio liquid at this point and there w il l '° S18 nnC<i to .! ,ho current passing 35 
electric tension on the lino at this noi, t 7 1 f ■ con ;? S V oni ' n S aad ™ "f 

the lmrmonical and other sounds P incident to bv ,l° U ? Wlth a ,noljil ° Paid all 
spending changes of Pr ° dU0 ° T 0 ' 

standing vertically instead of horizontally, asinFi^i.iL } 9 ro P ro .f ntfld “ J(1 
diaphragms c and c being dispensed with. In Fh? 2fi T^bn * P 0 ™ 1 * 8 of th ? 40 
narrow slits in tho partition b 1 between tbn e»ll= 2? i represented several 

the diaphragm i, running down at the sido of tbo \& m 8tri P, of motal 
tho slots in tho normal position do not corresnnn l P artltl< ®i and also slotted, but 
diaphragm, the openings are increased or lessened^ndtT’ f "° vibrat!ou of tho 
curront increased or decreased. d ’ and ^ 10 re siBtanco to the electric 45 

cell to tlie other boing a controlhid n b^a*vnlvo I '(n' J pluiinre pnssng0 , wn y from on0 
through tha partition. In Fig. 28 the nassami ° /’ armn g ed at an aperture 
colls by moaus of a flexible tube m und^tho oLnYn y • ■ bQtweon two independent 
movement of tho diaphragm acting’tlirougl ft fin™ ° r lc8sc,lod b >' th “ 50 

tube. I will mention that moremy mav bo usfd W VT MS u P on tbo floxibl ° 
porous material, such as paper, may se?ve to cnnl ! ° ad ?. f an ol “trolyto, or a 
sonts a piece of porous matorinl, such as naner or mnM ° M t ,°g° tbor - « ropro- 
liquidm the cells, so as to be kept moist P bv eanillorJ“V? t le onds P 033 into 
this is a pressor p, connected to the diaphragm to " 


Ellison's I mp/s. in Telephones and Apparatus Employed in Elcotrie Circuits. 

be moved by tho samo, and press with moro or loss forco upon tho moistened 
strip, anil interrupt tho passage of electricity more or less, according to tho 
amplitude of vibration. 

A Duluco dry pilo is combined with a diaphragm at each terminal for trans- 
5 milting and receiving sound ; this is shown in Fig. 31. D is a tube containing a 
Induce dry pile of many pairs; ono ond is connected to earth, tho other to a 
disk iP, facing a metallic diaphragm o connected to tho lino and distant station, 
whoro it connects to ft precisely similar apparatus. Tho movement of the 
diaphragm to and from tho disk causes a rise and fall of electric tension on the 

10 lino. , , , .. 

An clcclrophcrous, similarly combined, is sometimes employed for the same 
purpose, ns in Fig. 32. Tho base 1 of inetal is connected to earth. Upon said disk 
there is a disk of sulphur 2, charged with electricity that faces tho metallic 
diaphragm c, which Intter is connected to the line. The rise and fall of tension 
15 on the line is produced by tho movement of tho diaphragm to and from tho sulphur 


Calls arc combined with the telephone, so as to nttract attention to tho instru¬ 
ment. Those calls are operated by pendulums, forks, or reeds, which set up 
magneto-electric currents when vibrated, and from theso a bell or call receives its 
20 movement from the distant station. 

In Fig. 33 the tuning fork X is vibrated by tho electro-magnet x\ by waves set 
in motion by n similar fork at tho distant station; when tho fork has received 
considorublo vibration it strikes tho lover ar, which latter releases a clock move¬ 
ment that gives tho alarm. 

25 In Fig. 34 the fork X strikes tho boll and gives tho alarm. In Fig. 3o tho 
fork X closes a local circuit, and the bell is rung by a magnet and local battery. 
In Fig. 30 a polarized relay is used with its tonguo centered by a tightly drawn 
wire. This tongue closes the local circuit containing a magneto call-bell. In Fig. 37 
two magneto pendulums X serve to give the call; tho signaller lowers his bell 
30 and gives the pendulum a large swing by hand, which soon sots tho pendulum in 
motion at the distant station by tho currents which it sets up in tlio magnets n, n , 
which are polarized. 

Tho receiving portions of tho telephone aro of a character adapted to respond to 
tho clectrio pulsations from tho transmitting telephones aforesaid. Sometimes 
35 there aro two or more receiving diaphragms to ono air chamber to augment tho 
sound. 

Fi«, 38 shows a receiver provided with two metallic diaphragms d and two 
electro-magnets d' through which tho lino curront passes. Fig. 30 shows the 
armature diaphragms il arranged edgeways to tho opening in the mouth-piece, 
41) with magnets opposito i d 1 ni 1 gins This arrangement pormits of the reception 
of signals, but prevents tho transmission of any by magneto induction. I'lg. 40 
shows suvoral electro-marmots, each provided with a diaphragm, all included in one 
case, and all in the main line circuit; the sounds received aro augmented. 

Dampers may bo employed upon tho diaphragm of the receiving and trans- 
45 witting instruments to prevent false vibrations. Theso may bo the same as those 
shown and described in my British Lotters Pntcnt, No. 1044 of 1878. 

A diaphragm connected directly upon tho induction coil will respond to the 
electric waves, and givo nudiblo sounds. This dovice is shown in Fig. 41. _ 

In [dace of flexiblo wires for tho telephone connections, wires with universal 
50 joints are preferable. Long funnels may bo used with tlio tolophomo recoiver to 
increase tho volume of sound. , . . , , , ,,__ 

I he expansion or contraction of gases and otlior materials, by change of tempera¬ 
ture or hygromotric condition, are employed to vary pressure upon tlio carbon 
button or disk, between its two platina armatures, and a galvanometer in tho 
55 circuit by its movement indicates with the greatest and most absolute accuracy 
the oxteut of tho disturbing causo that is exerted on the carbon. In h ‘g- 42 is 
shown an instrument for measuring minute qualities of heat. A is tho carbon 




A.D. 1878.—N° 2396. 


Edison's Impts. in Telephones and Apparatus Em ployed in Electric CircuitT~ 

button, nnd 1, 2, tlio platina disks connected to tho battory B and galvanometer 0 
M is n strip of vulcanite or other material tlmt expands by heat. X is nn adjusting 
screw winch sorvcH to force M against tho disk and carbon, and bring sullicinm 
pressuro upon tho carbon to deflect the galvanometer to tho point whoro tin. 
carbon button is most sensitive to a slight pressure. When in a stato of rost tlm s 
lieat of tho hand acting upon M will expand it, and tho elongation causes tlm 
pressuro upon the carbon button to bo increased, bonco moro curront will mus 
through it, and tho galvnnomotor noodle will bo doflcotcd. In Fig. 43 is shown 1 
mercurial barometer with a float at b" to net upon tho carbon button The 
galvnnomotor G may bo wound difTorentinlly or placed in a Whontstono bridge in 
tho button being placed m one sido of tho balance. ^ ' 

In Fig. 44 the diaphragm at 12 is provided with n pin vnlvo tlmt idlows tlm 

SSrl"l- 0 ®" ”" 1th I 1 ’! 1 ’ 013 ^^ t0 ‘ ho W" 14 1 lll P ! 11 1 

1 ms dinphingm I.> is of iron nnd faces tho coro of n polarised magnet and it 

' n0 T, m0 r fl ;° m °» air than it would if noted upon by |j 

When TL ?Tt' X - diaphragm 15 vibratos in harmony with tlio diaphragm IS 
otherwise ^ 1S VI J ™ te< tho soun<1 vibrations of tho human voico or 

Within fl' >43 l tl '°tf inpl ' r ‘' Srn d an<1 Inoutll -P' cco is at the side of n closed box 

of w L Lto Tlm • m,0USly » tatinS 7 lind ° r ° f C,mIk ,P * on tho *"«>'<* 

ot wnicn lests tlio end of a spring arm <7, 1 secured to tho dinnhrnmn Tlm 
by'wator. 1 " 0 ^ 11 “ ^ or othcl ' “ducting electrolyte? and ii kept ,,S 

diaphragm 0 VlZZL t0 ?“ d,n ' k y ,ind « «»> other to the spring or 

* fr '* "i" * 

■ii u iS, 1 ^ ir'rs 1 

"SM::,."” s"tss». s ' “;f tt °»»• 

iS'EiS'i 1 i ,l ”. 

F?"io ,1”" I ?' 3 V P.ta.t MoS^oihs” 7."' |,,0,I “ “ 

,, =• JO shows a tube containing mercury, in which is a flout in i as 

vibrTIL 0 by tiio nLtl^'d^hTL t0 the if. The diaphragm will'bo 

through the same. Fig 47 showsTi tmr^’ Lt™' b> i 1,10 Ileftt ° f 11,0 curro,lt passing 
formed of disks securedTLthe d anTni ?" a 811111,1 mica condenser 

for tightening tho disks The Z me? of M prov ‘? od with nn ad > stin K ■«"» X 

40 

SSS* mnterial —LoSr^^slSyl pSS 

2s ?. $ s 45 


itli tho adjusting screw f diimlu-nm en 10 ] P n , ft 1 «nd 2 in combination 
Third. Tho combination of tmnSnP a”* "V’^-P^^HubstftntiaUy as specified, 
bell H, battery IC, an circuitsTrZ L ’ ,°° llS ^ swito1 ' 4 polarized relay F, 

forth and as sLwn in Fig 3 ^ “ °P oratill S substantially as heroin set 

coil tlio buttor™f I tompLlnokZaT°bTn ll0niCnnd i tl10 I ’ rimnr,5roil ' ouitofnn intluct,on 

and electro-magnet,''a'swin'gil^ToLor I pTaced*witli° iu'm 0 ™" 4 ’having a diaphragm 6 
tho receiving diaphragm, and*a switch o^koy Zr IncroaSng 1 "^ oTeotrio^rrent'anil 


Edison’s Impls. in Telephones and Apparatus Employed in Elect ric Circuits. 

operating tho lovor ns a soundor or call upon tlio diaphragm, substantially as sot 
forth aud shown m Fig. 4. J 

Sixth. In combination with tho tolophono transmitter B and rocoivor A tho 
induction coil C, D, battery Q, local circuit, switch S, nnd circuit connections 
5 substantially as sot forth and as shown in Fig. 4. ‘ * 

Sovonth. In combination with tho main lino circuit and local circuit nnd tho 
tolophonic instrument tho induction coil composod of two wiros, tho lar mat of which 
is surrounded by » finor insulated wire wound helically, tho two being 0 then wound 
into n helix to form tho induction coil, substantially as shown, and de“cribed in 
10 connection with Fig. 5. 

Eighth. Tho combination with an electro-mngnot of an iron or steol diaphragm 
secured to a resonant casn for rendering nudiblo acoustic vibrations, substantially 
as described, and shown in Fig. 7. J 

Ninth. The combination with a diaphragm vibratod by an electro-magnet of a 
15 resonant tube variable in its length, so as to adjust tho column of air to°tho tone 
of tho transmitting instrument, substantially as shown and described with reference 
to Fig. 7. 

Tenth. The combination with a vibrating reed aud electrolytic cells placed in 
»0 F' 6 °e CCtrie CirCUifc ° f a k ° y pIaC ° d ia a slmnt circuit < substantially as shown in 

Eleventh. The condensing coil 1, Fig. 8, arranged in tho electric circuit and 
operating substantially ns described. 

Twelfth. Tho induction coils 1, 2, 3, Fig. 9, electric circuits, and carbon trans¬ 
mitter, arranged nnd operating substantially ns aud for the purposes set forth. 

25 Thirteenth. The induction coils and electric circuits and carbon transmitter 
arranged and operating as described, and shown in Fig. 10. 

Fourteenth. Two or moro primary coils wound upon one secondary coil, as in 
Fig. 11, in combination with tlio electric circuits and carbon transmitter sub¬ 
stantially ns specified. ’ 

30 Fifteenth. The induction coil 1, resistance It, batteries B, electric circuits, nnd 
carbon transmitter, arranged aud operating as described, aud as shown in Fio. 12. 

Sixteenth. Tho induction coils G, II, telephonic instruments A, B, switch"^ key 
and sounder, arranged and operating in tho electric circuits, substantially as described 
nnd ns shown in Fig. 13. ’ ’ 

35 Seventeenth. The carbon transmitters h, h\ nnd induction coil D, E, nnd 
diaphragm c, Fig. 14, in combination with tlio batteries B, B, and electric circuits 
substantially as aud for tho purposes set forth. 

Eighteenth. The carbon button h and disks 1, 2, in combination with tho 
diaphragm o of tho speaking tube, arranged and operating as shown in and described 
411 "'‘tli reference to Fig. 15. 

Nineteenth. Tho combination with an induction coil of a diaphragm tlmt is acted 
upon by such induction coil, and gives out sonorous vibrations, substantially os 
described aud shown in Fig. 1G. 

4’ t /'r^' 1 ' c °mhination with tho balnnced circuits shown in Fig. 1G a 
’’ c f “j’homc instrument included in one circuit, and ucting to vary the electric condition 
us set fou by tko r0sisti,U00 that in controlled by tho sound vibrations, substantially 

1 wenty-fir.it. A transmitting telephono containing a variablo resistance in thn 
in Liu * 0 Cll °mt and a body acting by inertia, to vary tho resistance in proportion 
sound vibrations, substantially os described in connection with Fig. 1G. 
twenty.second. Tlio induction coils in local circuits or shunts at way stations in 
«nbination with tho tolophonic instruments, also in such circuits, substantially as 
“Ud for tho purposes described in and as shown in Fig. 19. 

!■ , twenty-third. The carbon transmitter h, lovor X, nnd diaphragm c, arranged as 
5a shown m Figs, 20 and 21. 

din ' 1 ! cut y- four th. Tho combination with a resonant case o 1 , Fig. 22, of tho lovor X, 
foitl c ’ ear h° n3 h and x\ disk k, and circuit connections, substantially as set 





Edison's Impts. in Telephones and Apparatus Employed in El ectric Circuits. 

Twenty-fifth. The npparatua ahown in Fig. 22, capable of receiving atmospheric 
and othor vibrations, and transmitting the samo olcctrically to a receiving telephone 
through a circuit wire and connections, substantially as sot forth. 

Twenty-sixth. The carbon transmitter in a local circuit, containing a secondary 
battery, in combination with tho induction coil D, E, connected in tho main and 
local oircuits, as illustrated in Fig. 23. 

Twenty-seventh. In an acoustic tolegraph apparatus, tho combination of two 
stationary electrodes immersed in two colls, a conducting fluid in said colls, and a 
fluid connection between such colls and mechanism actuated by a sound vibrated 
body for vaiying the dimensions of such liquid connection and tho conductivity of 
the same, substantially os set forth. J 

Twenty-eighth. Tho Duluce dry pile battery, arranged in connection with tho 
telephonic instrument, as illustrated in Fig. 31. 

Twenty-ninth. The electrophorous arrangod in connection with tho tolophonic 
instruments, as illustrated in Fig. 32. 1 

Thirtieth. A telephonic call consisting of a reed or tuning fork vibrated by an 
olectro-magnet, and acting to strike a boll, roloaso mechanism that sounds an alarm 
33 "al^nd^fi 088 a 1<>Cal ° ir0uit in wIlich is an alam or call > 03 illustrated in Figa 
Thirty-first. The polarized relay in a tolophonic electric circuit, and , “ 


lie, diflorences of weight, 


in f tube'e£ 1 tn h i'n- 1 ’ ,, ° dia P hra S la * the telephonic instrument connected to a 11, 
8 mercury and water, said diaphragm being vibrated by I 
Thirty-ninth 11 ThlPt - sul ? sta ? tl “ 11 y “a described in connection with Fig. 40. * 
47 ' mad8 ™«i • mica condens 

Witnesses, THOMAS ALYA EDISON, (us.) 






































































A.D. 1878, 7th Noveubeb. N°4502. 


Lighting by Eleotrioity. 


LETTERS PATENT to Edward Grimth Brewer, of tlio Firm of Brewer mid 
Jensen, of !!3, Clmncery Lane, ill tile County of Middlesex, Patent Agents, 
for the Invention of “ Improvements in Lighting iiy Electricity." A 
coinmnnicntion from nbrond by Thomns Alva Edison, of Menlo Park, in tlio 
State of New Jersey, United States of America. 

Sealed the 21et January 1871), and datod tbo 7th Novembor 1878. 


PROVISIONAL SPECIFICATION left by tlio said Edward Griffith Brower at 
the Office of the Commissioners of Patonts on the 7th Novembor 1878. 

Edwahii Griffith Brewer, of the Firm of Brower and Junsen, of 33, Chancery 
Lane, in tlio County of Middlesex, Patent Agents. “ Improvements in Lighting 
5 ny Electricity." (A communication from nbrond by Thomns Alva Edison, of 
Menlo Park, in tlio State of Now Jersey, United States of Amoricn.) 

According to this Invention the light giving material is employed in the form of 
cylinders or prisms consisting of finely divided metals, such ns platinum, iridium, 
ruthiniuiu, or other material having a high melting point, mixed with nonconductors 
10 such us magnesium or zircon oxides that are with difficulty melted. Tlicso aro 
Mixed and compressed into tlio proper form for the light, and rendered luminous 
“Ml incandescent by the passago of tlio electric current. 












Rpocllliutlnn. 


JpetUollotL 


A.D. 1878.—N° 4502. 


2 A.D. 1878.—N° 4502. 

Bmvcr'a Improvements m Lighting by Electricity. 


SPECIFICATION in pursuance of tlio conditions of tlio Loiters Patent filed by 
the said Edward Griffith Brower in tlio Croat Seal Patent Office on tlio 7tli 
May 1879. 

Edwaed Giuffito Brewer, of the Finn of Brewer and Jenson, of 33, Chancery 
Lane, in tlio County of Middlesex, Patent Agent, “ Improvements in Liauma 5 
BY Electricity.” A communication from ubroad by Thomas Alva Edison, of 
Menlo Park, in the State of Now Jersoy, United States of America. 

Tlio light giving dovico or candlo is in the form of a solid, such as a cylinder or 
prism. In the Drawing a form of candlo is shown that is convenient for use in tlio 
present Invention. ... 

Fig. 1 is a section of the candlo showing also tlio circuit connections. 

„ 2 is an enlarged section of tlio candlo detached ; and 

„ 3 is a perspective view of tlio candle portion x, which is a slightly tapering 
hollow cylinder, and split vertically except at tlio upper end ; this ensures uniform 
and comploto incandesceuco as tlio electric current passes up one side and down tho 15 

The boso is by preference enlarged, ns shown, in order that the electric conductors 
may be easily connected therewith, and in Fig. 1 a thermal circuit regulator is 
shown similar to that in Letters Patent No. 422G, granted Octobor 23rd 1878, in 
Groat Britain, to tho said Thomas Alva Edison. 20 

The electric current enters at n\ passes by tlio wire k to tho candle x, up one 
side and down the other, there being clamps to connect tho wires to tho bnso of tho 
split candlo, thence by the circuit regulator n, spring L, and clamp to the other wiro 
of tho circuit. 

If tho current is excessivo tho regulator n becomes heated, and expands so as to 25 
bring L into contact with the adjusting screw m, and short circuit the current and 
lessen its action in tho light. 

The special feature of this Invention rolates to the candle itself. 

Metals or oxides of metals aro mado uso of that produce in a comparatively large 
candle sufficient resistance to render tho wholo candlo incandescent. 30 

Finely divided metal or particles of rnotal having a high melting point are 
caused to adhere by earthy materials, such os magnesium or zircon oxides, or 
magnetic oxide of iron or other substances that are witli difficulty fused. Tho 
oxides of metals may bo obtained by chemical precipitation or otherwise, and tho 
candlo is moulded in either a moist or dry condition by pressure. 35 

Tho fine particles of metal may bo platinum, iridium, ruthinum, or other metal 
that can only bo melted at a very high temperature. Tho earthy materials should 
bo such os are infusible, such os oxide of magnesia or zirconium, lime, silicum, boron, 
or other suitable material. 

In cases where these oxides or earthy materials are mixed with the fhio motallio 40 
particles such particles aro thoroughly nnd uniformly mixed into tho mass before 
it is moulded, and hence such particles aro kept soparate by the earthy material, 
and cannot fuse or run together, nnd tho motallio oxides thomsolves aro olectric 
conductors to a greater or loss extent, and liouco may in some instances be used 
without tho particles of metal. In all cases tho substances aro mouldod and pressed 45 
into shape undor powerful pressure, and if tho particles do not adhere togethor 
sufficiently sugar, tar, silica, or similar material may bo used in moulding tho candles 
to shape, und theso substances may be volatilized by tho heat. 

The metallic particles aro rendered highly iucandcsoent, and the earthy materials 
or oxides also aro rendered luminous by tlio passago of tlio olectric current. 60 

In some instances tho rods or prisms of oxides aro saturated with a salt of metal 
difficult of fusion, and this salt is reduced to tho motallio state by heat, aud the 
metal permeates the.entire body in very minute particles, and theso particles ore 


Brewer's Improvements in Lighting by Electricity. 


not liablo to bo molted and run togothor in consequence of the intervening oxido or 

Ctt This Lavomtion is not limited to any particular form in which tho candlo may bo 
moulded or otherwise shnpod, but it rolatos to tho materials omployod in such 
5 caudles whereby tlio mass is adapted to tho passago of an electric current, nnd it is 
rendered highly luminous or ineandoscont by such current. . 

Having now described tho nature of tho said Invention and in what manner the 
mmo is to be performed, I declare that,— , . 

What is claimed os tho Invention of the said Thomas Alva Edison, and to be 
10 secured by Letters Patont is,— . , , , . 

A caudle or light giving body for olectric lights, ill which particles of metal or 
metallic oxido are moulded into a mass that is adapted to tlio passago of tho olcctnc 
current nnd rondored luminous by tho same, substantially os sot forth. 

In witness whereof, I, tho Baid Edward Griffith Brewer, have horouuto set 
15 my hand and seal, this Sixth day of May, in tho yonr of our Lord Une 

thousand oight hundred and seventy-nine. 

E. G. BREWER, (m.) 







































A.D. 1878, 28f/i December. N° 5306. 


Developing Magnetism and Elootric Currents, and Apparatus for 
Illuminating by Electricity. 


LETTUKS PATENT tu Thomas Alva Edison, of Monlo Park, in the Stalo ol 
Now Jersey, United States of America, lor the Invention of " IMPROVEMENT 
IX MKAN'S Foil DEVELOPING MAOSETISM AND ELECTRIC CURRENTS, AND IN 
APPARATUS Foil ILLUMINATING BY ELECTRICITY." 

Scaled the 28th February 1879, nud dated tho 28th December 1878. 


PROVISIONAL SPECIFICATION left by tho said Thomas Alva Edison at tho 
Otlice of the Commissioners of Patents on tho 28th December 18<8. 

Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United States 
of America. “Improvement in Means for Developing ILvonetism and 
5 Electric Cukukxts, and in Apparatus for Illuminating by Ellciriuia. 

The first part of my Invention relates to a dynaino-magnoto-olectrio machine. 
Ini Chinese! tins class electric currents have been developed in helices, andla 
portion of the current has been taken through the helices of the held of force 
magnets, and other portions have been employed in electric lights and for other 

10 In these machines the currents that pass through the field of force inngnete are 
expended simply in developing magnetism. 1 have discovered a method ot 
developing magnetism, and increasing the same to the maximum point « «o d.ag 
the power employed in rotating tho parts, without tho uso ot lichees around tl o 
15 held or force inap.ets j hence the electric current that is developed m the magne o 
electric machine can be entirely employed for lighting and other uses outside ot the 
machine, instead of a portion being used to develop magnetism. , 

When o niece of steel is brought within tho magnetic held of u peimnnent 
! magnet the same becomes a mag-net. I arrange a machine so that; the'induced 
I 20 magnetism rc-acts upon the permanent magnet to mcreaso its Iiower and th 
! develop magnetism by mechanical force in a manner somewhat similar to the develop- 
| luent of electricity in a magneto electric machine. 












2 A.D. 1878.—N° 5306. s j&!S“ 

Edison’8 Impts. in Means for Developing Magnetism and Electric Currents, ic. 

Ono of tho dovices I lmvo omployod consists of a shaft having radial bars, which 
is revolved with the onds of tho bars os near us possiblo to tho polos of permanent 
nmgnots, and tho other polos of tho magnets boing adjacent to tho hub or near tho 
other onds of tho bars. In their revolution tho bars bocome magnetized, and 
increnso tho magnetism in tho pormanont magnets until tho maximum magnetism 5 
is developed. 

Theso magnets aro omployod as field of forco magnets in tho magnoto electric 
machine. 

The dovclopmont of a continuous curront of olootricity is also dosirablo, for which 
purpose I employ copper rings or segments around an iron core, and I use mechanical 10 
revolution, whereby tho electric action, developed upon tho genoral principle of the 
copper disc between two magnetic poles, as oxporimonted upon by Arago, is con¬ 
verted into n continuously flowing electric current. 

I make uso of an electric candle composed of a strip of platina or similar metal 
that withstands a high temperature. Tho same is made by rolling out flat n strip 15 
that is thicker at one edge than the other, and at tho same time coiling it into a 
spiral. It is then coated with a pyroinsulator formed of some oxide or other com¬ 
pound or mnterinl, such as asbestos, that is fused with difficulty. The oxides aro 
preferably dissolved in an acid and applied to tho helix, and then the salt decom¬ 
posed by heat. The helix is compressed into a compact cylindrical form, and it is 20 
rendered incandescent by tho passage of the electric current, mid by its expansion 
it is made to regulate tho electric current and prevent injury to tho light giving 
body, ns in a Provisional Specification heretofore filed by me. A resistance or 
rheostat is thrown in or out of circuit, either automatically or in diroctmg tho 
current through tho candle, so ns to maintain uniformity of resistance. 25 

The aforesaid helix may bo polished on the outer edges of tho coil, or a cup be 
used around tho same. When finely divided iridium or similar metal not easily 
fused is mixed with an oxide, such as the oxide of titanium, iron, or other metal 
that acts os a conductor when highly heated, the resistance is lessened in proportion 
to the heat, and by properly proportioning the mixture tho bar or candle is self 30 
regulating to prevent the heat becoming too great. 

Tho conductors aro largest near tho source of electric energy, and decrease in 
size in proportion to tho number of lights that have boon and aro to be supplied. 

I provide a magnetic safety switch actuated by an electro magnet, so ns to supply 
to each building only tho current required, and to disconnect the circuit if tho 35 
current is too powerful or the wires in tho building come into contact. I also 
provide for storing the electric current or energy, so that tho same may bo used as 
required. This is done by tho uso of secondary batteries, and there are dovices for 
shifting tho current from one secondary battory to another periodically, so that ono 
may be in use wliilo tho other is being charged from the main circuit. Induction 40 
coils when used should be placed with thoir primary coils in a shunt from tho main 
conductors with curront shifting dovices, and tho secondary currents developed by 
induction are used in the electric candles. 


A.D. 1878.—N° 5306. 3 


Edison's Impts. in Means for Developing Magnetism and Electric Currents, &c. \ 


SPECIFICATION in pursuance of the conditions of tho Letters Patent filed by 
tho said Thomas Alva Edison in the Groat Seal Patont Office on tho 28th Juno 
1870. 

Thomas Ai.va Edison, of Menlo Park, in tho State of Now Jorsoy, United States 
5 of America. “ -Imwiovement in Means for Developing Maonbtism and 
Electric Currents, and in Apparatus for Illuminating dy Electricity.” 

One part of this Invention relates to an electric lamp or burner mado from a wire 
or strip of platina, platinn-iridium alloy, or other metal which fuses at a high 
temperature. This wire or strip I coat with an oxide of metal, such as corium, 
10 lime, magnesia, or other inotal or material which will not be injured by a high 
degree of heat; this coating I term “ pyroinsulation.” 

Tho wiro or strip may bo pyroinsulated by dissolving the oxido in an acid, coating 
tho wire or strip with the solution, and then passing the wiro or strip through heat 
from a (lame or otherwise, to decompose tho solution and cause tho doposit of the 
15 oxido upon tho wiro or strip. 

If the burner is mado of wiro, tho wiro after boing pyroinsulated is wound upon 
a spool or cylinder of lime or other infusiblo material, and when the burnor is 
placed in an electric circuit and tho circuit closed, tho electricity passes through tho 
entire length of the wiro of the burner and brings it to incandescence. The metallic 
20 oxido forms a pyroinsulnting coating that protects the metal of tho wire, and 
renders it more difficult to fuse, and prevents tho electric current passing from ono 
coil to the next, thereby compelling tho current to travel the entire length of tho 

If the burner is made from a strip of metal, the same should bo thicker at one 
25 edge than tho other, so that it may be rolled to an uniform thickness, at the samo 
time that it is coiled into a spiral. The strip of metal should be thin, so as to 
obtain considerable length in a short spiral. Tho spiral or helix thus mado is pyro- 
insulatcd, as aforesaid, and then compressed into a compact cylindrical form. 

Sometimes tho pyroinsulating mntorinl is placed as a layer between the coils of 
30 the spiral or helix. 

When tho expansion and contraction of tho burner a is mado to regulate the 
amount of current to the burnor, the helix or spiral is placed-between heads 2, 3, 
ns shown in Fig. 1, and the rod b is connected to the upper head 3 and also to the 
lover v. The lower head 2 is supported by tho legs i, 4. The spiral expands or 
35 contracts ns a whole, nnd gives motion by tho rod b to tho bent lover c, which latter 
opens and closes the circuit at 5. When c is away from 5 the current enters by 
wire 7 and passes to tho burnor, thenco by rod b, lever c, and wiro to tho line. If 
the current becomes excessive the heat expands tho spiral, raises tho rod b, and 
moves the lover c into contact with 5, short circuiting or shunting tho current, so 
■10 that it pnsses by the route having tho least resistance, going by 7, 9, 5, c, and 8 to 
lino. A resistance coil equal to tho resistance of tho burner may be placed in this 
short circuit. 

Tho lover c is a safety device which closes tho short circuit through tho screw 10, 
in case c nnd 5 should fail to rnako electrical contact. 

45 Fig, 2 shows in onlargod sizo a burnor mado of tho flattened pyroinsulated wiro, 
tho exterior of tho burner may bo polished, or tho pyroinsulating material may be 
wholly removed from said extorior surfneo. 

Fig. 3 shows a porspectivo view of a burnor composed of six helices of pyroinsu- 
latcd wiro, enoh helix being wound upon a spool of infusiblo material, such as lime, 
50 and tho spools secured to a divided disk of tho same matorinl supported upon 
metallic rods or half cylinders. Tho wires 7 and 8 of the lino connect to opposite 
helices as shown, and tho helices aro connected to each othor, honco tho current is 
obliged to pass through all tho helices, and brings each holix to tho samo degree of 
incandesconco. 








Edison's Impts. in Means for Developing Magnetism and Electrio Currents, £o. 

Tho thermal regulators sot forth in my British Patont of Oct. 23, 1878, may 
ho used for regulating the current to humors mndo like those in Figs. 1, 2, 3, 
the special foaturo of this part of my present Invention relating to tho burner mndo 
of a wire or strip of metal coated with a pyroinsulatiug material for tho purposes 


aforesaid. 

This pyro-insulating coating allows of very line wire being used for tho burner, 
honco several layors of the wire may bo wound upon tho spool of infusible material, 
and tho burner will havo a resistance of several hundred ohms which permits of 
several hundred burners or Inmps boing connected quantitivoly in multiple arc, 
without requiring largo main conductors. ' |0 

In Fig, ‘1 tho burner a is mndo of pyroinsulatod wire, and said burner is sur¬ 
rounded by a motnl cylinder a 4 which becomes incandescent from the heat of tho 
burner, and radiates the light. Tho expansion bar b\ when tho heat of tho burner 
exceeds a pre-determined point, moves the lever c, and opons tho circuit between c 
nnd 5, and closes tho short circuit 9 through 5 and C, in which short circuit thero is 15 
a resistance R equal to that of the burner ; this arrangement of thormal regulator 
and circuits is similar to that shown in my aforesaid Letters Patont. 

All tho burners of wire or metallic strips shown in my aforesaid Letters Patent 
may bo coated with tho pyroinsulating material. 

In Fig. 5,1 have represented a menus for pyro-insulating tho wire, consisting of a 20 
carriage fitted to move back and forth under tho stretched wire, and enrrying a 
sponge c 3 moistened with the pyro-insulating solution, nnd a lamp for drying tho 
coating applied to the wire. The sponge is moistened with a soluble salt of tho 
pyroinsulation, such as tho nitrate, oxalate, or acetate of lime, zirconium, magnesium, 
or cerium, nnd its group of metals, whoso oxides aro infusiblo after being heated 25 
The first passage of tho wire in contact with tho moistoned sponge lays a vory thin 
layer of the solution on tho wire, and the heat from tho flame which is behind tho 
sponge serves to decompose the salt, driving off tho acid and leaving an adherent 
oxide upon tho wiro. This operation may be repeated many times, each time tho 
deposit becomes thicker, until the oxido has reached a thickness of about ono third 30 
that of tho wiro itself. Tho wiro should bo wound upon a spool having a largo 
circumference before boing wound upon tho spool of tho burner to provent tho 
cracking of tho oxido. 

In some instances I mako a burner or candle of finely divided iridium or other 
metal that is not easily fused, mixed with an oxido of titanium, iron, or otlior metal 35 
which acts as a conductor when highly heated ; this is to be mouldod into tho 
desired form, nnd by properly proportioning tho mixture, tho current to tho burner 
is regulated by tho heat of said burner, the rosiBtanco beiug lessoned in proportion 
to the heat. 1 r 

Another feature of this Invention relates to the arrangement of tho main con- 40 
ducting wires so os to obtain a completo metallic circuit, and at the same timo take 
advantage of the conductivity of tho earth, so that tho moss of metal in ono of tho 
conductors may be reduced ; tho cnrtli and metallic conductor servo at tho samo 
time as a protection for the insulated conductors. Fig. G is a diagram illustrating 
the connections. 45 

Tho magneto electric machines may bo of any suitable character and driven by 
power. They may bo arranged between tho two main conductors A, B, in ranges 
or multiplo arcs of three, four, or more in each, and tho connections should bo for 
intensity. I have represented four such magneto electric machines M in each range. - 
A is a tube laid in tho earth and preferably of iron, nnd it forms together with tho 50 
earth ono half of tho circuit; within this tube is an insulated conductor B, pro- 
lerably of a number of strands of coppor twisted togother in tho form of a cable, ono 
strand of the cable being droppod, say, every 100 feet, so that at tho extreme end of 
the circuit there shall be but a singlo strand. This cablo is insulated from tho tube 
by any cheap or economical insulation, such as tar or nsphnltum. A branch tube 55 
containing a single strand from tho cable is to onter each house or building, nnd 


tpeeisution. A.D. 1878.—N° S306. 5 

Edison's Impts. in Means for Developing Magnetism and Electric Currents, Sio. 

from tho bnsemont smallor wires are run to tho various parts of tho houso whore 
tho lights aro required, 

Each lamp is to bo provided with a switch 22 so that it may bo disconnected 
from tho conducting wires. 

5 The electric generators nt tho contra! station arc provided with constant field of 
forco magnets, the helices of which are in tho electric circuit, honco if all the Inmps 
feeding from the main conductors aro disconnected by tlioir switches tho oircuit will 
bo broken nnd no current passes through tho conductors luading from tho station to 
the lights, henco tho steam ongino driving tho magneto machines runs lightly nnd 
10 with tho oxpondituro of a vury small amount of force. If now tho switch of a 
single lamp is turned tho lamp is connected to tho branch wires from tho main 
conductors, tho circuit is closed, and only sufficient current passes from the control 
station to supply that lamp because the external resistance determines the amount 
of current. In this way tho current will bo proportioned to tho number of lamps 
15 in the circuit. Each lamp I prefer to contain a resistance, when incandescent, of 
1000 ohms. As before described, the connecting of one or more lamps causes a 
sufficient amount of current to be developed at the contra! station to keep tho samo 
incandescent, it follows that if the machines at the station are arranged expressly 
for tension and quantity many hundreds of lamps may ho placed in circuit botweou 
20 the main conductors, tho reduction ol resistance upon placing each lamp in circuit 
drawing the proper quantity of current from the station, hence the greatest economy 
possiblo is obtained by causing all the resistance outside of the main conductors to 
be light giving resistances. 

In Fig. 7 I have shown a safety device for shutting off tho current from tho main 
25 wire to the house in case the wires should get “ crossed,” or from any other causo 
the current passing to tho house should become in excess of that required for the 
burners, m is an electro-magnet in tho same circuit as tho burners. The armature 
lever of this magnet is kept upward by means of a spring resting against an adjusting 
screw, and the tension of this spring is to be such that the lever will not bo attracted 
30 until the current passing through the magnet reaches a certain intensity. When 
so attracted the lever is separated from to 1 , latched at to 2 , and the circuit broken to 
the house, hence no injury results to tho burners from tho excess of current on tho 
line. Word must now be sent to the central station, and when tho fault is remedied 
the lever m 3 is unlatched by baud nnd tho circuit again closed to tho houso by tho 
35 lever to 3 coming in contact with to 1 . 

Another part of this Invention relates to means for storing tho electric current 
or energy so that tho same may be used as required. This is done by tho use of 
secondary batteries, and there arc devices for shifting the current from one secondary 
battery to another periodically so that one may bo in use while tho other is boing 
40 charged from the main circuit. 

In tho diagram Fig. 8 tho circuit connections are illustrated. Fig. 9 ib a 
perspective viow of tho switch; and Fig. 10 is a side viow of the socondary 
batteries. 

Tho secondary batteries A 3 , B 3 , are of any desired construction. I prefer and use 
45 two sheets of lead wound togother into a square or cylindrical form and immersed 
in acidulated water in a closed case. The main lino a 3 is connected with any 
magneto-electric nmchino or otlior sourco of electric energy, and 6* is tho return lino 
or earth connection, Tho main lino o s is connected by tho wires c- to tho secondary 
batteries A 3 , B 3 , and tho return wires tl a , <?, pass through tho switch / and wiro i 
50 to ii 2 . 

The electric lamps are represented in branch circuits between tho wires h and k. 
The wiro h connects to ono end of tho secondary batteries A 3 , B s , and tho wiro k 
connects to tho switch/. 

Tho switch / is profombly cylindrical with two insulated half cylinders 14 and 15 
53 against which tho springs or <?, d?, rest, and from these half cylinders are metallic 
connections to tho insulated disks 1G aud 17 respectively, against the peripheries of 





6__ A.D. 1878—N° 6306, _s WC i telM . 

Edison's Impls. in Means for Developing Magnet ism and Electric Currents, <tc, 

wlrioh tho springs of i, ft, rest, and this switch can bo rotated periodically by a 
handle, or by clook-work, or other suitable means. 

When the switch / is in one position the main circuit is closed through a}, c\ A* d‘ 

U, 10, and i to h 2 , and tho secondary circuit is closed from B 3 through ft, lamp’s a 
wire k, switch 17,16, and wire e 2 to B 3 . When the switch / is in tho othor position fi 
tho main circuit from o a passes by c a to B 3 , and by c a , 14,16, and i to b\ whilo the 
secondary circuit from A 3 is by ft through lamps a, wire ft, 17,16, nnd wire d? to A 3 
so that when the secondary battery B 3 is furnishing the accumulated electricity to 
tho lamps a tho main current is charging the secondary battery A 3 , and vice versa. 

When a secondary battory is fully charged tho decomposition of tho liquid in 
commences and gases are developed. 1 avail of this to actuate a circuit regulator 
nnd disconnect the main current. b 

Tho two closed eases in which the secondary bntterics are placed are provided with 
tubes s passing to a chamber r beneath a flexible diaphragm t, nnd in tho metallic 
circuit or there is a switch or levor u that is acted upon to brenk tho electric circuit is 
to the secondary batteries when tho gases have accumulated sufficient to move said 
diaphragm. The accumulated gases combine, and in so doing maintain tho electric 
closed by tliVlever l>atterl0S ’ and t,u> P res3ure decreases and the circuit is again 

ih“ g - n r^°i i)edth 1 e T naturo of tho 8aid Mention, and in what manner 2 0 
tho same is to be performed, I declai*e that ^ 

I claim a8 my Invention,— 

First. An electric lamp or burnor made of a wiro or strip of motnl coated with 
T Innter i a ' 3ub3tan , tiall y 113 and for ^0 purposes specified. Second. 

of metal with intervening pyro-insula- M 

casl a 3d su™?inSto bi, ?i atl ?. n With “ i burn T f ° rmed of Py roin3 “>“tcd motal tho motnl 
° bUn,0r and made ' nCandeSCCnt ^ thereof, sub- 

combtinn innZn^lf I , >™ insula , ti . D e «> B wins « “trip of metal for the conductor, 30 
similar mate™ 1 nn fu TJ lrB °{' 3 ^ r, P through a solution of lime, magnesia, or 
8 “ a fl0me t0 efIb0fc decom P os ‘tion of the 

the F earth7h 0 fi i ^hl eC l met f i0 c , onduBto 1 1 ; 3 within a metallic case which forms with 
with e etr e lamr,, nn,f ' . sub . 3blnial y a3 specified. Sixth. Tho combination 35 
nections at,,1 IwTh d | 1 malacircuit of two secondary batteries and circuit cou- 
and substantially as sot forth, to alternately change the main and 

secondary circuits, substantially as specified. * 

dianWmor 1 iiJr b !i nat - i0n '''l itl , 1 a secondary battery and its enclosing case of a 

41 

si «• uiSss srf:£"“surr 

l " mt ° 45 

Witnesses, THOMAS ALVA EDISON, (ml) 

Cha 3 H. Smith, 140, Nassau St„ N.Y., 

William G. Moit, 140, Nassau Str,, NX 6 „ 

For Her Majesty’s Stationciy Offico. 






























A.D. 1878, 23 nl October. N° 4226. 

Developing Electric Currents and Lighting by Electricity. 


LETTERS PATENT to Tliomns Alva Edison, of Menlo Park, in the State of 
Now Jersey, United States of America, for the Invention of "Improve- 
MEN " r in' the Method or and Means rou Developing Electric Currents 
and Lighting nr Electricity." 

Sealed the 14th January 1879, and dated tho 23rd October 1878. 


PROVISIONAL SPECIFICATION left by tho said Tliomns Alva Edison at tho 
Office of the Commissioners of Patents on tho 23rd October 1878. 

Thomas Alva Edison, of Menlo Park, in tho State of Now Jersey, United 
5 n os °*' America. 11 Improvement in the Method op and Means for 
developing Electric Currents and Lighting nv Electricitv.” 

I make use of an electric gonorntor in tho form of a very largo tuning fork, the 
to magnetised or not, and the samo is firmly supported in the middlo, 
o™ the free ends are vibrated by mechanical force, such as small steam cylinders, 
10 „ i “ l ’ iston rotl connected to each end of this fork, or any other device, such as a 
wank, may be used to keop tho free ends in vibration; but little power is required 
0 kce P «P the rate and amplitude of vibration that would result if the free ends 
''are drawn aside and then allowed to vibrato liko a tuning fork. Tho mechanical 
mrce applied to keop this largo fork in vibration is converted into electricity by 
15 u P° n the fork soverol magnets, and opposito to them stationary electro- 

““gnets, tho helices of which are so connected by commutators that tho induced 
wrent set up in the holicos by tho approach and recession of the cores will bo con- 
Si n t0 1 in ° upon 11,0 P™ 10 *? 1 ® 8 known in connection with mngnoto-oloctric 

20 J l,e , elcc W<! enorgy thus set up is carried by a wiro to the lighting apparatus next 
sinfl i ’ or il may Lo used at a distant station for vibrating by magnetism a 
llM large tuning fork, from which mechanical movement can bo givon by tho 
[•Price U] 

















2 A.D. 1878.—N° 4226. sSSS. 

Edison's Improvement in Developing E lectric Currents cfc Lighting by Electricity. 

notion of a pawl on a wheel or a crank moved by tho mechanical vibrations of tho 
tuning fork. 

The electric light is dorivod by tho passago of tho curront through a spiral coil 
of wire, or through a loaf or strip of metal, or through carbon or any other material 
that will become incnndesccnt. Tho incandescence of bodies under electric action 5 
has boon known, this portion of my improvement relates to tho mnnnor of rogu- 
atmg tho curront, so tliut it can nover beeomo so intonso as to molt or injure tho 
light-producing body. To offset this I mnke use of an automatic apparatus that 
becomes operative according to tho intensity of tho curront to check, divert, or 
partially neutralize the action of the current in tho light-giving body. 10 

The heat developed is caused to expand a wire or othor body either by tho 
passngo of electricity through it or by its proximity to the source of light, and this 
expansion gives a mechanical movement through a lover or similar devieo to operato 
a circuit closing dovico, to shunt or short circuit more or less of the current, or to 
throw a resistance into the circuit, and thereby lessen tho electric current passing 15 
through tho light-giving body and prevent injury to tho same. The same result 
is attained by the expansion of confined air acting 011 a diaphragm, or by directing 
a curront of air upon the light-giving body to lessen the temperature thereof. And 
m some instances I employ a secondary battery in a local circuit, that is opened or 
closed mechanically to throw the electric energy into the coils of plntina or othor 00 
light-giving bodies; a number of these coils or light-giving bodies are placod in 
one circuit, and means employed for proventing tho breaking of tho circuit by any 
injury to ono of the lights. 3 J 


.Edison’s Improvement m Developing Electric Cmrcnta <6 Lighting by Elcetrioity. 

SPECIFICATION in pursuance of the conditions of tho Letters Patont filed bv 
lprin87o! 10mnS A V “ Edl301 ' thn Great Soal Patont Offico on tho 23rd 

Developing Electiuc Cuihients and Lighting nv Elkctmcity;" M 
Tho first feature of this Invention relates to a means for developing a curront of 
electricity by mechanism, so as to obtain the necessary electrical foreo cheaply and 
the second part of tins Invention relates to tho electric light itself tho method of 
10 regulating the intensity of tho light and preventing injuiy to tho .Z “ and tlm 
peculiar dovicos that are employed 111 au incandescent state to givo tho light, 

It has long been known that if two oloctro-magnets, or an electro-mmmot and 
a permanent magnet, bo drawn apart or causod to pass by each othor, that oloctrio 
currents will bo sot up 111 tho helix of the eloctro-mn<met 
15 It.1ms also boon known that vibrating bodies, such ns a tuning fork or a reed 

can be kept in vibration by tho exercise of but little power. I avail of those two 
known forces, and combine them in such a manner as to obtain a po verf. e e ic 
curront by tho expenditure of a small mechanical force 

c 0 I?r ' lWin r g a i.i Uni r e / 0I ' k is rc P rese,,ted " s attached to a 

-U stand b , this fork is preferably of two prongs, but only ono mbdit bo omnloved 
uiion tho principle of a musical reod. This vibrating bar or fork may b- (Two 
metres long more or lass, and heavy in proportion fit luus its regular rate of 
'ibration like a tuning fork, and the mechanism that keeps it in vibratm- i« to 
25 iTIn,.'? '“VT? V a C1 r nk Und ,r ov . olv * n g 01 otl ei t bl cl si r 
tho™‘]! yCd ' lUt 1 I,r0fel ' " 8ma11 ah - ^ or wat0 ‘- “"g™ “PPlied to each end o* 

The cylinder a 1 contains a piston and a rod b' that is connected to tho end of tho 
bar, and steam, gas, wator, or other fluid under pressure acts within tho cylinder 
30 vni ng n n m,t < ; C Cra 5 ?? ono “ ido of 1,10 I'iston and tlien the othor by a fuitablo 
30 valve; the valve and direct-acting rod c 2 are shown for this purpose. 

Iho bar or fork a, 2 may be a permanent mngnot or an electro-magnet, or olso it 
IS provided with permanent or electro inagnots. I have shown an eloctro-mu"uet c l 
tl I e I a e ™ 1 H 1,l ' 0llg0f r t ! , , U f< J rk ; tliero u “y be two or more on each, and opposed to 
« ■' are .'T. co r ca .°f t j 10 0 ectro-magnots d, hence as tho fork is vibrated a current 
, “p 1,1 tlle ijolix of encli electro-magnet d in ono direction ns tho cores approach 
each other, and in tho other direction as they recede. 1 

Ihis alternate current is available for electric lights, but if it is desired to con- 
vert tho current into ono of continuity in tho samo direction a commutator is 
an !i"i -i ° |10ratccI V tll<! vibrations of tho fork to change the circuit connections 
polarity tU>n ’ a “‘ tllerob y mako tho Pupations continuous on the lino of ono 

A portion of tho curront thus generated may pass through the holices of tho 
ciectro-mngnets c 1 to intensify tho same to the maximum powor, and tho remainder 
10 curront is employed for any desired olectrical operations wherever available. 
LsJT'r US ° t ,'“l. s ! l,no 0S P° ciall y witl > my electric lights, but I remark that 
electricity for such lights may bo dovoloped by any suitable apparatus. 

l have represented commutator springs or lovers c 1 , c', operated by rods that 
s mo through the levers o a , o', and by friction move them. When tho prongs o 2 , a 3 , 

,- n !!! ovl "g from each other tho contact of lovers c 3 , o', will be with tho screws 
, !l, ! d tbe current will bo from lino 1 through c 1 to c, thonco to e 2 , to 41, 43 

nnu to circuit of eloctro-magnots d, d, and from d, d, by 42 to 40, c* and line as 
lb - tCd ', by .V, 11 ; 01 ' r , 0WS - When 1110 P ro ngs or, o?, are vibrating towards each other 
circuit will bo through c 1 , c, c 3 , 42, in tho reverse direction through tho circuit 
and magnets d, d, back to 43 and by c* to line. 










4 A.D. 1878.—.N 0 4226. Sptolaaltel . 

Edison’s Improvement in Developing Electric Currents <£• Lighting by Electricity. 

Platinum and other materials that can only bo fused at a vory high tomporoturo 
have been employed in olectric lights, but there is risk of such light-giving sub 
stanco melting umlor the oloctrio energy. This portion of my Invention relates to 
the regulation of the electric current, so ns to provont the samo becoming so intenso 
ns to lnjuro tlio incandescent material. The current regulation is primarily effected s 
by the heat itself, mid is nutomatic. * 1 u 6 

In Fig. 2 I have shown the light-producing body as a spiral a connected to the 
posts b, c and within the glass cylinder g. This cylinder has a cap l and stands 
upon a base to, and for convenience a column n nnd stand o of any suitable 
character may bo employed Most of the other Figures are in the form of diagrams in 
to more clearly represent the electrical connections. I remark that it is preferable 
to have tho light within a case or globe, and that various materials may bo employed 
such ns alum water, between two concentric cylinders to lessen radiation, retain the 
heat, and lesson tho electric energy required, or colored or opalescent glass or 
0 U 1 11 1 leJ “ rofrangibility of tho light, such ns sulphate of quinine 15 

pi iere^or°i' i ‘a'vacu m™ ° tU<l 1 ° U '° 1, S^t S nnd the light may either be in tlmntmos- 15 

stances ar?sot 1 L t ifhmlnftS,^ nd eSpCOi “ lly adnptcd t0 USe 88 sub- 

-J 1 ' 0 - 0 , 1 ? 011 ' 10 . cil ' e ‘! it ' F js- 2 - by line 1 to tho post r and by a wiro to tho 20 
Si turn It :r r0d h ; SP 1 ‘ wire ?’ t0 thB P“t C, thigh the double 2 ° 
f’., ‘ 0 po , at .r' , d 11 . met i ll,lc connection or wire to the post n and lino 4 

and so on through the electric circuit and the light be developed in a 

heift dVvItd 1 J 3 H P '" ,d !n Pr01 :°;, ti0 " t0 thu h f lt * tlio coil or in proportion to the 
1 ™i !n d i 3 1 ff'ss'igo oi the current through the fine wiro *, and if tho 95 
^o 7Z:tTr ly / i njU ^ l ° l !’ e ft PP’ lratus ■» prevented by tho expansion ' 
£ .7 ° the le ver/ to dose t!,e circuit at i nnd short circuit or shunt a 

aroi^nd'whkh^arboMs madoto^adimi VI ^ b ° dy fonne ' lof a P Itlfc!na or similar wire 45 
the action of tho electric current by pressuro; tho snm ° becomes luminous by 

toiEthS I? & *• -fety 

thereby break tho circuit • thn ™ n I°7 ” , w 0 k or 00,1 0 should fuse and 
i. to line 4 when switcli a’ is in “ t 'wTthll ,'-"h C0 ,1 V} 0 t l ,oi,, t 2, and block 50 
but whoa x is movod to 3 the cnUt’Ll, ‘J", 8 tllrow . s ‘ho light out of action j 

is broken the spring lover f closes to land lino 4 > but if a or k 

a to i and line 4. 8 1 1 laod ouric "tgoes by \,f t, to 3, nnd by switch 

lever/MdMmrtTiwuSu the^mren/from fS' "’d' 1 2 Pf® 88 , 0 * tho s P rin 8 . 1 up0 " 53 
of „„,1 tasistance to J,“ 


spedikAtioA A.D. 1878.—N° 4226. 5 

Edison’s Improvement in Developiwj Electric Querents c6 Lighting by Electricity. 


In Fig. 10 tho switch * when at 3 allows the current to pass through tho 
resistance coil R or rheostat that is of equal resistance to tho light-giving material, 
5 so tlint othor lights are not influenced by lighting or extinguishing one electric light; 
tho other parts are liko Fig. 2. 

Fig. 11 represents an electric light liko thntBhown in Fig. 0, only aspring and arm 
/ tako the place of tho lover. 

Fig 12 corresponds to Fig. 7 exeopt that the spring arm / is used instead of tho 
10 lover. 

Fig. 13 ropresonts a carbon pencil or rod nnd spring levor; the carbon itself in 
this enso expands when tho current is too strong nnd the spring short circuits tho 
curront and becomes as boforo an automatic thermal regulator. 

In Fig. 14 tho light-giving body a is ropresonted as a strip of plntina or similar 
15 foil, and tliore is a safety switch t in tho form of a spring, and this is used in addition 
to tho spring or lover/, so that in case of tho spring boing interfered with nt i by 
dust or oxyd upon tho contact points tho rod h by a slight additional expansion 
touches tho safety spring t and short circuits tho curront. 

Fig. 15 represents two strips of plntina a, a\ If tho strip a expands under heat 
-0 so as to causo levor/to leave spring lever/' and break the circuit, that cannot 
lmppon until tlio spring/ 1 rests upon tho contact point i; this allows tho olectric 
circuit to divido and pass through both a and o*; this reduces the temperature of 


both and tho twi 

25 In Fig. 10 tho lover spring /■ when it comes in contact with i closes the 
shunt circuit through tho rheostat It, that lessens the power of the current on tho 
plntina strip a. The spring s is adjustable to maintain tho proper tension on the 
lever/. 

In Fig. 17 the end of tho spring lever / rests upon a small plntina wheel 10 
30 that is upon nn arbor in jaws at tho end of the scrow 11. When this screw is 
turned one way it causes tho wheel to touch the spring nnd extinguishes the light 
by short circuiting it. Wlion tho screw is turned the other way the contact is 
broken and tho light induced. By tho movoment of the jaw and roller up nnd 
down tho plntina wheel is rovolvcd progressively by two stationary spring 
35 pawls 12 and 13 acting on a ratchet wheel on tho arbor of tho wheel 10. By 
this devico a now contact surface is brought into action each time the light is 

In Fig. 18 tlireo bent levors / are Bliown, the vertical ends being in a eup of 
mercury to which one line wiro is connected. Tho circuit passes through these 
■10 lovers/and foil a, but when tlio foil becomes too hot it expands and allows the 
levers to make contact with i and short circuit tho current; one of tho tlireo lovers 
will ho almost suro to operate, but if not and tho light-giving body a still expands 
tho point 15 will touch tho spring 10 and throw tho circuit through tlio resistance 
lb In placo of the levers last described tlireo or moro springs may be usod, as in 
+5 Fig. 19, tbo action being the snmo ns levers ; or four or moro springs may be used ns 
in Fig. 20, there being an adjustable spring 18 to apply a slight tonsion to the strip 
plntina and to preserve tho continuity of tho circuit should the springs fail to 
connect. Tho automatic thormnl circuit regulation is in some instances effected by 
, dm heat given by tho electric light to air or gas in a confined vessel. Tho apparatus, 
oO Fig, 21, corresponds generally to that shown in Fig. 2, except there is a diaphragm 
v of thin metal or othor material across below tho perforated bnBO that holds tho 
glass g, so that this diaphragm will bo prossed downward by tho expansion of the 
nir contained in tho glass, and when tho maximum tempornturo is obtained tho 
curront will bo short circuited by tho point on tho diaphragm making contact with 
00 tho insulated spring 21. Tlio current passes by the wire 1, metallic head l, incan¬ 
descent strip a, metallic baso to and column, to tho lino 4. When tho heat of tho 
spiral roaches within a few dogrees of the melting point of said spiral the air in the 


■0 maintained in the circuit until the contraction of a separates 











G A.D. 1878.—N° 422C. spodjcuion. 

Edison's Improvement in Developing Electric Currents it Lighting by Electricity, 

'glass g lias become expanded and tlio diaphragm is bulged outwardly and makes 
contact within tlio spring 21 and the curront is short circuited; tlio current now 
"being through wire 1, spring 21, diaphragm v, metallic base m and column, to the 
lino 4. If the circuit should fail to close by tlio contnct of the diaphragm and spring 
: 21 the further movomont of the diaphragm will bring tlio spring 21 in contnct with 5 
the screw i, and tlio short circuit will bo through tlio spring 21, seraw i, and metallic 
column to the lino 4. It is to be understood that in all cohos tho notion of tlio short 
circuit or shunt is momentarily to lessen tho curront through tho light-giving sub¬ 
stance, and tlio circuit-closing devices play up and down at tho contact point 
maintaining uniformity of brilliancy in tho light. Id 

The device shown in Fig. 22 acts tho same as before indicated, but the coil is 
horizontal and tho wires reach it by passing through a piece of chalk or similar 
matorial resting upon a base m and tho short circuiting is by contnct with tho screw 
i of a platina projection on the diaphragm. A spring circuit closer nmy bo used as 
shown in dotted lines. If mercury or a liquid is introduced in tho confined space, 15 
containing also tho light, and the air or gas heated thereby, a tubo may lead to a 
circuit-closing cup, ns shown in Fig. 23, to short circuit tho current whon tho 
maximum temperature is obtained. 

In lighting by electricity it is often important to uso a secondary battery in 
connection with the main current. The diagram, Fig. 24, shows four electric light 20 
coils a, a, a, a, in a secondary circuit containing cells S, B, with plates iu a conduct?!!" 
liquid, and the lover 28 is vibrated by an electro-magnet 20 or by clockwork; when 
the lovor 28 is in contact with 39, tho current from lino 1 passes through 29 and 
S, B, to 4, but when 28 leaves 39 the lino is closed, but a local circuit is made 
between 28 and 30 through the coils a and secondary battery, tho discharge of this 25 
secondary battery gives the light, and the movement is so rapid that tho light 
appears continuous. A single secondary battery may bo introduced with one or 
more lights, as in Fig. 25, the expansion of the light-giving material short circuiting 
the current through tho secondary battery S, B, tile light-giviim device may be a 
spiral such as that shown in Fig. 2, the same being illustrated by dotted lines. A 30 
coil cr may be used in a vessel containing water or other fluid ns seen in Fi" ‘>0 
Bnid coil being of less resistance than the light, so as to heat the water and operate 
the circuit-closing diaphragm. Instead of a rheostat in the shunt circuit I some¬ 
times employ a button of carbon 32, as seen in Fig. 27. In this case tho spring 
lever / bearing »upon the carbon button lessens the resistance by the increase of 35 
pressure as the platina strip expands, and as it contracts and lessens the pressure on 
tiio carbon button the resistance of that carbon button increases and a greater 
portion of the current is sent through tho platinum strip; this regulation is very 
accurate If a helix of wire 33 is placed in the same position as the carbon as seen 
1 a, ii . actlon Wl11 bu th0 samo - for who “ 1,10 Mils of tho helix touch each 40 
other the resistance will bo less in the shunt than when the helix is distended by 
the contraction of the platina strip or wire a, and tho proportion of current passing 
through a may be increased by the contraction of a, and tho reverse. This con¬ 
struction prevents electric sparks, ns the motallic circuit is continuous. When an 

ls ' n ‘ ro .‘ laood 1 in tl,e eli;ct,io circuit - nnd its armature spring is set 43 
s .° tbat W11 not rcs po"d until tho maximum current is flowing 
tlnough the circuit, then tho movomont of the armature can bo mndo to short 
lessen t 10 1 , * ht ^ ,v, J l ? , bo ty , ns “'"strated in tho diagram, Fig. 29, nnd thereby 
rheostat T? f °T ont a f tbo b S bt ' , 01 ' lfc mny bo made to throw in a resistance or< 
lhcostat K to , en Mo How of the curront, ns shown in Fig. 30. Ono lover / or 60 
l&hfcF °‘Th 11 r 0801 ' Inay re° raade .to regulato tho flow of electricity through several 
Tho diagram, Fig. 31, illustrates several lights placed in one or mom 
remdnf«. 01t w- lto ’oS" 011 lg H bein 2 regulated independently by its own thermal 
aUka un’nev 32 J“f >rc “ e, ? ts ran S 0S of lights, ono branch circuit boing connected 
at the upper ends of tho lights, and the other circuit wires to tho lower ends to the 35 
liahu'S which th °f 0l8 ‘ r F ' e ‘ v 3 i i , U . U8tl '“tos toe circuit connections of ranges of 
lights, m winch tho top of ono light is connected with tho bottom of tho noxt, the 


Edison's Improvement in Developing Electric Currents di Lighting by Electricity. 


A vnrioty of holiccs, coils, ribbons, and other forms of light-giving materials are 
illustrated iu Fig. 34 to 42, nnd in Figs. 48, 49, and 50, and I remark that in ull 
3 cases the light is duo to tlio incandescence of the body, and that tho thermal 
regulator of tho circuit is to be adjusted or made to act automatically to losson tho 
electric curront before tho samo becomes sufficiently intonse to injure tho light¬ 
giving substance; this point will vnry according to tho material employed in tho 
light. A cylinder of platina foil around a rod of limo gives an excellont light, nnd 
10 strips, wires, rods, beads, and pieces of iridium, ruthinum, rhodium, osmium, titanium, 
and other metals that fuse at a high temperature may be used ; also conducting 
oxides nmy bo used, such ns oxides of titanium. In Fig. 43 tlio two strips of 
platina «, a 1 , are connected at their ends to the Inrgo nnd small pulleys 50 and 51, 
nnd the lower end of a is connected to tho spring / nnd of a 1 to tho block 52. If 
15 the foil a 1 expands, it allows tho pulleys to be rotated by tho spring /, drawing off 
foil from 50, and thoroby increasing the length of tho foil that is incandescent, and 
increasing tho rosistanco in tho circuit. The same effect is produced by the dovico 
shown in Fig. 44, in which the axial electro-magnet a 0 lias a suspended core; ns 
the electric current increases tho core is drawn into the helix and the pulloys 50 
20 and 51 turned so ns to lengthen tho strip of foil o. Fig. 45 shows a cylinder 
of platina foil a as tho light-giving material. Fig. 46 shows a magnet a 7 in the 
wire between 1 and i. Whon tho spring / touches i tho current passes through the 
magnet, and its armature closes a metallic circuit that divides tho olectric curront so 
that it does not ull pass through the foil. In Fig. 47 tho lover /, as it descends, 
25 comes into successive contnct with tho yielding points 56, and tlio current passes 
more freely from 1 to 4 in proportion ns the one or more of the resistance coils may 
lie short-circuited by the lover/ 

When tho electric force is generated by a magneto-electric machine, it is important 
to regulate tho speed of tho machino in proportion to tho strength of tlio current, 
30 so as to prevent injury to tho machine when tho electric lights are extinguished. I 
effect this either by an index or galvanometer nt tlio central station to denote to tho 
engineer tho strength of tlio current, so that he can regulato tho machine, or olso a 
governor is omployed to throw in rosistanco or to short circuit the electric 
current. 

35 Fig. 51 is a modification of the dovico shown in Fig. 21. Thore is a chamber g- 
connected by a tubo to tho glass g, and this chamber g- is covered by a diaphragm 
j 3 , over which is a lever /. Whon tho spiral a reaches its maximum heat, the 
expanded air nets upon the diaphragm <f and moves tho same, so that it is brought 
in contnct with tho lovor/; this in its turn makes contact with tho screw i, and the 
40 current is short-circuited. 

Fig. 52 shows another arrangement of parts, whereby tho heated air in the 
glass g operates tho lovor that short circuits tho curront whon tho burner reaches 
its maximum heat. The glass g rests upon tho top of the case or box h\ and within 
this box there are flexible chambers h\ h\ similar to thoso used in an aneroid 
45 barometer; there iB an oponing in tho top of tho box, through which a tube from 
the chamber it* passes, so that tho air mny havo freo passngo from the gloss globe or 
shade g to said chnmbors. Upon tho under part of tho lower chambor there is a 
lover/ connected thereto at f* and pivoted nt /°, nnd a contnct point /° on said 
lover is contiguous to tho lever /’ that is pivoted to the adjustable block/ 3 . 

"0 Tho current onters by tho fine 1 and passes by tho screw 23, spring 22, and wire 
to tho lover f, thenco by contact /”, and wire to tho motallic support /'“and 
burner u, nud by tho other motallio support / u to tho wire 30 and line 4. Whon 
tho maximum liont is attained by tho humor, tho heated air as it ospands acts 
within tho flexible chambers h\ h\ and bulges thorn downwardly, moving tho 
55 lever /, and bringing tho point / 6 in contact with the lever f, and breaking the 
circuit between f and /» to the burner «. Tho current now passes by line 1, 









8_ A -°- 1878.-N” 4226. 8pcoltalh0i 

Edison'* Improvement in Developing Electric Currents,{; Lighting by Elc cM^j. 

wiTsMoTjoi 22, Wir ° 2 *’ l0V01 ' P ‘ °° ntO0t P ‘ ' OVOr f> rosistm]co coiTuT^d 

• Tho resistance R is equal to that of tho humor a, and said rosistanoo nrovonfs 
OXCOSS.VO sparks at tho con (act points. Tho block /», upon which thoCSW 
“f / , nr “ ll0 ‘]. w movable, and is adjustable by tho soiow /> By moving 5 

t m.mh V t 5 ) '« 1 ' d!< t l0 . ^urnor, tho circuit is broken to tho lamp and closed 
sprh a 03 and sL’w n " d n-"i d °m S tho oircuit fro,n 1 «* b ™kcn bet e tl 0 
automation lly conneoted! 0 * *^ ^ rUV ° rS ° n0nmmt ^ th ° hm P to 

52 «* composed of six spirals connected as shown in 1(1 
Tig. So, so that tho oloctnc currant passes through all of them 1 

» " 4 th ° samo arrangement of circuits is shown as in Fig. 52, but tho heated 
air nets upon mercury in a tube to expand tho mercury, move a flout and 0 a n 
Md /- “ nd the circuit to ttic lamp, and close itT ^ 

In tho sectional I elovation, Fig. 5G, and sectional plan, Fig. 57, tho thermal retm 15 

rm o^ S raeW so h, t R r' n 7 ^ th ° *“ m l> 18 uponTswing^ 

7 . °, 1 . urncKot » fi0 be swung like a mis fixture. Tlio bracks „« ,*«, 

insulated aii Ut • 1 ™ °?° of the clectric conductors ; the same is 

ftgsB„ 

S,“E„£3 thut 

««k 11...,./! ™ rkr "'•*« » 

a deposit upon tho t dn nllto P;r P „ n ' tl °," atl j f l’ mntlt y P a83i "g through tho cell ofl'ects 
deposited, Sso on kuho’eml of ^7 aoaneBM ’ doobfe tho quantity is 
■ by the inipeotoi to thfcenlal oin If "° d ’ "ft ° n ° ™ nt . h ’ tho P lat ° is **«• 
copper upon tho thin plate will be nrnI < l(" <!0UI wly woigllied. As tlio deposit of 
passing into tho ho-so tho samo 1 P 10 P 0rtl0Ded to tho total amount of ouiTcnt 45 
charge for tho electricity supplied be °° mos 11 «««>* measure or standard for the 

“sx‘r 11 ” r> “ ta 

placed in ono branch, and in another h™™!" 1 ? i“’ mv , ln& sa /> 1000 ol, ms resistance 
burners a 2 , n? a t j„ ono i n . , Jrnnc ‘ * bavo shown lour electric candles or 50 
in two branch Jirouito, tooi T ' S 7 ° ° P™xin.ity and arranged 

star to ~ »*“ 4 sS3"‘ u ::s,e « 


Edison's Improvement m Developiny Electric Curve 


* it Liyhtiny by Electricity. 


In Fig. 50 tho thermal regulation is effected by the olectro-mngnots e' : , o 7 . Tho 
current from ono lino passes through tho spiral a, and thon through tho oloctro- 
inngnets o°, c 7 , lover e", contact screw c 2 , lover e 10 , and sorow e" to the other lino 
wire 4. Tlio lovers nro provided with rotrnctilo springs, and their tension is 
5 adjusted so that tho magnets will not attract tho levers if tho currant is of such 
intensity as to produco tho proper incandescence of tho light-giving body ; if tho 
intensity of tho current should oxccod this proper point, then tho mngnuts attract 
their lovers nnd keep thorn vibrating, thus breaking tho circuit at tho points e J 
and e 11 , nnd weakening tlio currant passing through tho burner a. 

10 Two magnets nro used in order tlint the spark at tho contact points may be 
lessened. 

Fig. GO shows tho same form of thermal regulator as tlint shown in Fig. 51), but 
only one lmignot is employed. 

In Fig. G1 the lover e' of the electro-magnet c r ’ acts upon a lover c 12 that has a 
15 spring to draw it towards c u . When the current is of tho proper intensity tho 
circuit passes through the spiral a, magnet c°, lover c 12 , and contact c 11 to tho lino 4; if 
the current becomes too intenso tlio lover of c r ’ is attracted and tho lever c 12 is moved 
from c 11 breaking the circuit to the burner; this is but momentary, for the 
spring o 1 * draws tho lover c“ upwards, and this latter moves the lover c 12 , again 
IP closing the circuit to the burner, and if tho current continues to bo too intense, the 
lever c’ is kept vibrating, opening and closing tho circuit and weakening tho current 
to such an extent ns to prevent all danger of tho fusion of the light-giving body. In 
Fig. G2 tho lover c r ' acts upon a lever c 12 atid opens tho circuit moro quickly than by 
tho direct action of the lover c*. 

!5 In Fig. G3 tlio circuits nro so arranged that the magnet c“ is in a branch circuit 
and tho current divides, part going to tho magnot nnd tho principal part to tho 
light. If the current becomes too intense the magnet attracts the lever c" and 
breaks tho currant at c 2 . 

Fig. G4 shows a magnet provided with two coils, the current passing through in 
10 opposite directions. The coil i r ’ is of largo wire and is ill the main circuit with the 
burner, while the coil i 7 is of great resistance and shunts the burner and coil I' 1 . 
Tho inequality of tho resistance of the burner produced ,by rise of temperature 
serves to disturb tho balance, the magnet i 7 becomes energized and attracts the 
_ lover i" and opens the circuit. 

15 Fig. Go shows a thermal regulator consisting of a bunt tube containing mercury, 
which latter is expanded or contracted by' tho heat of the current passing through 
tho same. A float in tho mercury at tho open end of tho tube is connected to tho 
lever/, and there is a second lever/ 1 provided with a contact point or screw that 
presses upon /* so long as the electric current is of tho proper intensity. As tho 
:0 mercury expands and by tho float raises the lever /, the lever/ 1 rises also and 
presses the continuity of circuit until /' touches the stationary contact i; then if 
the mercury continues to oxpand/separates from /' nnd the circuit to tho burner a 
is broken. 

Tho device shown in Fig. GG operates tho same ns that in Fig. 0U, but the electro- 
5 magnet is adjustable nearer to or further from its armaturo lever in order that said 
lover may vibrato quickly or slowly according to tho distance of tlio armature lovor 
mid magnet from each other. In Fig. 07 the lovor c s is kept away from the 
magnet c° by a flat spring c 17 instead of a retractile spring; said spring c 17 is upon 
a block moved by tho sorow c 1 " so that tho spring cun boar with more or less 
0 lmcssuro upon tho armature lovor and thus dotormine tho point at which tho lovor 
will bo attracted by the magnet and consequently regulating the amount of current 
passing to tlio burner a. 

Iii Fig, G8 a thermal regulating coil is shown within tho iloxiblo aneroid 
. chambers A 6 , A 11 , tlio heat from tho coil acts upon tho air within said chambers and 
o operates tho levers// 1 , tho sumo as lias been described with roferonco to Fig. 52. 

I claim as my Invention,— 

First. The combination with an electric light of a thermal circuit regulator to 
















10 A.D. 1878.—N° 4226. sp^n^ 

Edison's Improvement in Developing Electric Currents <Si Lighting by Electricity. 

lesson the eloetrio action in tho light when tho maximum intensity 1ms been 
attained, substantially as set forth. 

Second. Tho combination with tho elcetrio light of a circuit-closing lever oporated 
by heat from the olectric current or from the light, and a shunt or short circuit 
to divert the current or a portion thereof from tho light, substantially as set 5 
forth. 

Third. Tho combination with the eloetrio light and a resistance of a circuit closer 
oporated by heat, and serving to placo moro or less resistance in tho circuit of tho 
olectric light, substantially as set forth. 

Fourth. Tho combination with an olectric light of a diaphragm operated by tho 10 
expansion of a gas or fluid in proportion to tho tomperaturo of the light to regulate 
tho electric ourront, substantially as sot forth. 

Fifth. Tho combination with a vibrating body, similar to a tuning fork, of 
mechanism for maintaining the vibration, and magnets, cores, and helices, wheroby 
a secondary current is sot up so as to convort mechanical motion into eloetrio force 15 
or the roverse, substantially ns sot forth. 

Sixth. Tho combination with electric lights, substantially such ns described, of 
means for regulating tho electric current to the same in proportion to the heat 
ovolved in the light so as to prevent injury to tho apparatus, substantially as set 
forth. 20 

In witness whereof, I, the said Thomas Alva Edison, have hereunto sot my 
hand and seal, this Second day of April, A.D. 1879. 

THOMAS ALVA EDISON, (its.) 

Witnesses, 

Stockton L. Griffin, of Menlo Park, N. J. 25 

George E. Carman, „ 
































































A.D. 1879, 17th June. N° 2402. 


Eleotrio Lights and Apparatus for Developing Eleotrio 
Currents, &o. 


LETTERS PATENT to Thomas Alva Edison, of Monlo Park, in tlio Stale of 
New Jersoy, United States of America, Eloctrieian, for tiio Invention of 
" Improvements in Electric Lights, and in Apparatus for Developing 
Electric Currents and Regulating the Action of the same.” 

Sealed the 14th October 1S79, and dated the 17th June 1879. 


PROVISIONAL SPECIFICATION loft by the said Thomas Alva Edison at the 
Office of tlio Commissioners of Patents on the 17th June 1879. 

Thomas Alva Edison, of Menlo Park, in the State of Now Jersey, United 
Slates of America, Electrician. “ Improvements in Electric Lights, and in 
5 Apparatus for Developing Electric Currents and Regulating tub Action 


I have ascertained that when wires or sheets of platina, iridium, or other 
metallic conductors of electricity which fuse at a high temperature are exposed to 
a high temperature near their melting point in air for several hours by passing a 
lu cu >Tent of electricity through them and then are allowed to cool, the metal is found 
to bo ruptured, and under the microscopo there is revealed myriads of cracks in 
every direction, many of which nro seen to reach nearly to the centre of tlio wire. 
1 have also discovered that contrary to the received notion platinum and iridium 
alloy loses weight when exposed to tlio hent of a candle, that even heated air causes 
it to lose weight, that the loss is so groat that it tinges a hydrogen flarno green, 
and under tlio influence of an electric current and at a yellow wliito heat tlio loss 
is very great After a timo the motal falls to pieces, hence wire or slieots of 
platinum, or platinum or indium alloy, as now known in commerce, are useless for 
20 by '"“"defence. . 

itirst, becauso its loss of woiuht makes it expensive and unreliable, and causes 
the burner to be rapidly destroyed. 

oocond, because its electrical resistance changes by loss in weight and its light 
B'Ving power by the cracks or ruptures, the melting point being determined by 
tne weakest spot where the greatest difference of potential of the electric current 
“ present, which causes this point to be brought to a higher heat than the rest of 
0 surface of the wire; again, as it is essential to obtain a steady light the 
t^ricc 10d] A 
















2 A.D. 1879.—N° 2402. iSSS. 

Edison's Improveme nts in Apparatus for Developing Electric Currents, etc. 

platinum burner must be screened from tlio air, and when thus screened by boing 
placed in a glass vossol the glass soon becomes coated with a black deposit of 
platinum. 

A platinum spiral brought to incandescence under these conditions may bo made 
to give a light of tlirco standard candles when near its melting point, and when the 5 
radiating surface is 3 / u of an inch, but this amount of light will be rapidly reduced 
as before described. 

From my researches and experiments I am led to believe that the causo of tho 
rupturing of this metal when brought to incandescence is due to tho action of the 
gases contained in the pores of tho metal. These gases aro probably compressed 10 
within tho pores during the rolling or drawing of tho sheet or wire. 

These gases or air when subjected to high heats are greatly oxpandod and 
rupture the metal, and it cannot be driven out by slowly heating the metal. 

I have also discovered that the loss of weight and apparent volatilization of tho 
metal is due to the action of the air or gases against tho highly heated surface. 15 
Having thus ascertained tho cause of fracture and loss of woight I linvo conducted 
experiments to obviate theso defects, and havo succeeded by the following 
method A spiral of platinum wire is placed in a glass bulb, with its ends passing 
through and sealed in the glass, and tho air exhausted from the bulb by a Sprengel 
pump, until tho discharge from a three inch induction coil will not pass between 20 
two subsiduary wires in the bulb, tho ends of which aro four millimetres apart; 
tho wires of the spiral are thou connected to a magneto electric raachino or battery 
whose current can bo controlled by the addition of resistance. Sufficient current is 
allowed to pass through the wire to bring it to about 150° Fahrenheit; it is allowed 
to romnin at this temperature for 10 or 15 minutes ; whilo thus hoated tho air or 25 
gnses in the pores of the metal is expelled by tho action of the bent and tlio 
expansion of tho gases which tend to pass outward in consequence of the vacuum. 
While this air or gases is passing out of tho metal tho mercury pump is kept con¬ 
tinuously working. After tho expiration of about 15 minutes the current pnssing 
through tho metal is to bo augmented so that its tcinporatnro will bo nbout 300 30 
degrees Fahrenheit, and it is allowed to remain at this tomperature for anothor 10 
or 15 minuies. If the mercury pump be worked continuously and tho temperature 
of the spiral raised at intervals of 10 or 16 minutes until it attains to vivid incan¬ 
descence, and tho bulb be then sealed, tho metallic wire is then in a state heretofore 
unknown, for it may have its temperature raised to the most dazzling incandcsconce, 35 
emitting a light of 26 standard candles. 

Whereas before the treatment the same spiral would only omit a light equal to 
three candles before attaining the melting point. The wires subjected to the 
process of freeing them from air and gases are found after the process to have a 
polish exceeding that of silver, and obtainable by no otlior means, no cracks can 40 
bo seen oven nfter the spiral has been raised suddenly to incandesccnco many times 
by tho current, und no volatilization takes placo ns there is no doposit upon tho 
glass bulb, nor does a delicate balance show any loss of weight in the spiral after 
burning lor many hours continuously, because tho spiral is in iv vacuum that is so 
nearly perfect that tho action of the gaseous molcculos is reduced to the minimum, 45 
and wore it possible to obtain an absolute vacuum there would bo no loss what¬ 
soever, and tho total loss after a year’s use would scarcely bo noticed. I havo 
further discovered that if an alloy of platinum and iridium, or even platinum be 
coated with tho oxide of magnesium in tho manner hereafter stated, mid subjected 
to the vacuum process described, that combination lakes placo botweon the metal 5U 
and the oxide, giving tho former rcmarkablo properties. With n spiral, having a 
radiating surface of “/io of an inch, light equal to that given by 40 standard candles 
may bo obtained, whereas tho same spiral not passed through my process would 
molt before giving a light of 4 candles. 

The effect of tho oxide of magnesia is to harden tho wiro to a surprising extent 5 
and render it moro refractory. A spiral spring niado of tho wire is as clastic and 
springy when at dazzling incandescenco os whon cold. 


fqWbft A.D. 1879.—N° 2402. 3 

Edison's Improvements im Apparatus for Developing Electric Currents, &e. 

1 havo found that chemically pure iron and nickel drawn in wires and subjected 
to the vacuum procoss may be made to give a light equal to that of platinum in 
the open air. 

Carbon sticks may be also freed from air in this manner and be brought to a 
6 temperature, that tho carbon bocoraes pasty, and if then allowed to cool is very 
homogonoous, nnd hard rods or plates made of mixtures of finely divided con¬ 
ducting and non-conducting materials may thus be freed from air. It is nlso 
obvious thnt the metal might bo heated by subjecting the containing bulb to a 
considerable tomperature, but this only partially frees tho wire from its air or 
10 gases. 

I will now describe the form of burner of lamp which I employ. 

To operate several hundred electric lights practically, each equal to an ordinary 
gas jet, upon one circuit, it is essential for many reasons, both on tlio score of 
economy, facility, and reliability, to place them all in multiplo arc, and to prevent 
16 tlio combined resistance of several hundred lamps from falling to such a low point 
as to require main conductors of immense dimensions with low resistance, and 
generating machines of corresponding character, it is essential to revorso tho present 
nnd almost universal practice of using lamps which have but ono or two ohms 
resistance, nnd construct lamps which shall have, when giving their proper light, a 
20 resistance of several hundred ohms, because tho moro lamps there arc in circuit the 
less will bo tho resistance. I liavo ascertained by experiment that tho loss of 
energy is in proportion to tho extent of the radiating surfaco independent of the 
resistance of the conductor; hence wo liavo 100 lamps, each of l / t of an inch 
radiating surface, and each of 1 ohm resistance, or 1,000 lamps having tho same 
25 radiating surfaco nnd 1,000 ohms resistance each; the loss of energy from each 
lamp, when giving each a light of 15 candles, will be nearly the same, but the 
combined resistance of the 1 ohm lamps will bo of an ohm, requiring an enor¬ 
mous main conductor, whereas tho combined resistance of the 1,000 ohms lamp will 
be 1 ohm, requiring a conductor of very moderate dimensions. In practice, a 
30 resistance of 200 to 300 ohms in the burner will be sufficient. 

Again, with lamps of low resistance, tho lamp connections nnd leading wires 
must be large to prevent great loss of energy by resistance, the leading wires from 
the mnin conductors nro large, oxpensivo, and bulky to linudlo, tho low resistance of 
the burner or incandescent conductor requires large terminals to convoy tho current, 
35 and these offer by their conduction a medium for the rapid dissipation of energy 
without producing nny effect, whereas with a lamp of high resistance nil those 
objections are obviated. 

My burner consists of n bobbin composed of an infusiblo oxide, such ns oxide of 
calcium, cerium, zirconium, magnesium, freed from silica, nnd turned in a latlio from 
40 sticks moulded by hydraulic pressure in a mnnnor hereinafter set forth. 

Theso wires servo to hold the bobbin in tho centre of tho sealed glass vacuum 
bulb and at tho samo time servo ns conductors of the electric current to tho wire 
coiled upon tlie bobbin. 

Tho two platinum wires nro first passod through small tubes of glass which are 
45 melted round tho wires. The burner is introduced into the bulb and the wires aro 
passed out through the sides of tho narrow neck loading from tho bulb, and the 
glass is melted around them to prevent leakage, the glass of the neck being melted 
to tho small gloss tube around the wires. 

Before tho burner is permanently sealed at tho neck tho air pump is connected 
50 therewith and tho wire upon tho bobbin is subjected to the vacuum process hereto¬ 
fore described, and tho electric current is used to produce incandescence for about 
one hour to heat tho bobbin nnd thereby oxpel tlio air and gases, after which tho 
oalb is permanently sealed by molting tho glass of tho neck, nnd it is ready to bo 
ased as a lamp. 

55 Tlio method which I adopt for regulating tho light radiated from the burner 
consists in a small rotating magnot provided with a governor which sorves to open 
tho lamp oirouit when the strength of tbo current is greater than is necessary to 






i A.D. 18*79.—N 4 2402. 


Edison's Improvements in Apparatus for Developing Electric Currents, <6<j. 


produce the proper light in the bobbin. This apparatus is very reliable, and 
although tho current supplied is not perfectly continuous tho total energy passing 
to the lamp in ono hour is nearly tho same, no matter what tho strength of the 
current may be. Tho magnets are so arranged that tho continuous inotnllic circuit 
cannot bo broken by tho commutator of tho revolving magnet and the extra current 5 
produced by tho reversal of tho current in the revolving magnet is short circuited 
by tho fixed magnet, licnco tho sparks which would occur at the break points of 
tiie governor are prevented. 

The rotating magnet is upon a vertical shaft supported in suitable bearings, and 
immediately over tho rotating magnet is tho fixed magnet, tho cores of which are 10 
in tho patli described by the rotating magnet Upon tho shaft is a rovorsing 
■commutator formed of an insulated ring, tho periphery of which is faced with 
platina and cut in two parts, one part being connected by a wire to ono holix of 
tho revolving magnet and the other part to tho otlior helix of said magnet, tho two 
helices being connected. Rubbing on this ring are two contact springs which servo 15 
to convey the currents to the revolving magnet. 

Tiie curvcnt passes through the fixed magnet, thence througli tho revolving 
magnet, the rotation of tiie magnet being kept up by tho reversal of the direction 
of flow of tho currents through the revolving magnet. 

When the cores of tho revolving magnet are nearest tho cores of tho fixed magnet 20 
the direction of tho flow of current is reversed by tho action of tho commutator 
springs and commutator, and tho polarity changed; lionco tho attraction ceases, but 
tho momentum of tho rovolving magnet carries said magnet forward, nnd mutual 
attraction again takes place j as the revolving cores npproach the stationary cores 
tho current is reversed nnd tho revolution continued. 25 

Connected to tho revolving shaft is a govornor which consists of two collars 
connected together by two springs; one collar is secured to the shaft while tho 
other is freo to slido thereon. 

Upon each spring a weight is secured, nnd tho rotation of tho shaft causes these 
to act centrifugally, nnd bow outwards the springs, and raise tho sliding collar 30 
upward, more or less in proportion to tho speed of tho shaft. 

The sliding collar is made with a groovo to receive tho end of tho circuit opening 
lever, which lever is moved by the rise and fall of the collar. The otlior ond of the 
lever has an insulated cross bar which is in contnct with two circuit breaking 
springs, and serves to disconnect tlio springs simultaneously from their contact 35 
points or blocks when the shaft has reached a certain velocity. 

The object of using two springs is to open tho circuit at two places simultaneously 
nnd thus reduce the spark, which it does in tho ratio of the number of simultaneous 
breaks. 

One of tho two springs is connected by a wire to one of tho commutator springs 40 
and the other is connected to tho wire leading from the mnin conductor or a branch 
therefrom. This method of breaking tho circuit simultaneously in many places is 
applicable to all kinds of electrical apparatus whore largo and powerful sparks 
occur, os, for instance, if it is desired to transfer electric energy from ono point to 
another by. dynamo ciectric machines operating upon a magneto electric motor at a 45 
distant station. If four springs aro employed and tho circuit opened at tho four 
places simultaneously the spark will be reduced to of what it would bo if it 
was opened at but ono placo. 

The block to which tho two circuit breaking springs aro secured is connected to 
a screw so that said block nnd springs can be positioned or adjusted with rofcronco 50 
to tho cross bar on tho governor lever. 

By turning this screw to the right tho block and springs aro moved until tho 
cross bar moves the springs away from their contact points or bars, ami disconnects 
tho lamp from the circuit; the reverse movement places tho lamp in circuit, and, 
according to the proximity of the springs to tho cross-bar of the governor lover, so 55 
the amount of current to tho burner is regulated. A stop is applied to tho screw so 
that it can be turned only to a determined point which limits the amount of current 


A.D. 1879.—N° 2402. 


Edison’s Improvements in Apparatus for Developing Electrie Currents, do. 

passing to tho burner. I prefer that each burner shall give a light equal to 1G 
candles, tho bumor being capable of giving 35 candlo power without fusion. 

As thoro may be a point where the rovolving magnet, after being at rest, will not 
start when tho current is put on, I uso an automatic starter which consists of a light 
6 lever nnd thin armature turned edgewise, which is attracted by the fixed magnet 
at tho momont tho current is put on. Tho movement of this lever, which carries 
upon its ond a click, serves to givo a suddon motion to tho Blmft of tho revolving 
magnet by the click engaging in a ruchot or toothed wheel secured to tho shaft. 

Tho click, after mnking this movement, passes beyond tho ratchet and does not 
10 como in contact again until the magnet is stopped and tho current is broken. 

In tho Specification of my British Patent, No. 530G, of 1878,1 have described tho 
manner of coating tho wire with pyroinsulntiug material. I employ that mode in 
coating tho wire, after which a coil of snid wiro is wound upon ono or more lime 
’ supports nnd placed in a sealed bulb that is connected to a Spengel vacuum apparatus, 
15 nnd by gradually increasing the heat of tho wire by tho gradual rise in tho strength 
of the current, as described in tho first part of this Specification, tho wiro is not only 
freed from air and rendered moro refractory, but tho oxide is vitrified and shrinks 
upon the wiro, from which it cannot be detached. 

The coil, after passing through this process, may bo wound upon the lime bobbin 
20 of the lamp without breaking tho pyroinsulation. 

After the bobbin is wound nnd placed in tho final bulb it lias any air which may 
hnvo passed into tho oxides expelled by a gradual accession of current in the manner 
heretofore described, and tho bulb is then sealed. 

The oxides of the alkaline materials which aro infusible attack the plutiua to a 
25 slight extant, and, ns herewith, greater tonacity to it than the oxides which do not 
attack it, such as cerium or zirconium ; but the compound thus formed renders tho 
wiro more refractory. 

It is not essential that tho oxide should be in the form of a soluble salt, as it may 
be put on the wiro directly by mechanically mixing tho oxido with water, alcohol, 
30 or other liquids, but special devices aro requisite to keep tho mixture iu constant 
agitation to prevent sottling. 

It has been found vory difficult to mould slender sticks of tho oxides enumerated 
on occouut of the bonding nnd brenking of tho plunger of tho mould, which, owing 
to tho pulverulent nature of most of tho oxides, must be long and slender. 

35 I have obviated this difficulty by dovising a mould and plunger by which 
pressures to the crushing point of steol may be concentrated upon ono quarter of an 
inch surface. 

This apparatus is applicable to tho moulding of any substance. 

Tho block that recoives the mould is of cast iron, with a taper hole in tho contra. 
40 Tho mould is made of three pieces, and has the same tapor as the hole in tho block. 

The object of tho taper and split mould is to allow tho pressed piece to bo taken 
out without injury, which it would receive were it forcod out of tho mould endwise. 

The plunger is upon tho end of a sliding stock, and snid plunger is only about 
1 of an incli long nnd about of on inch in diameter, and it is adapted to pass 
45 downwardly into the liolo in tho centre of tho split mould. 

After tho mould has been filled to tho top with the pulverulent oxido a steel 
washer or punch section is placed upon tho oxide nnd forcod into tho mould by tho 
plungor. Afterward another punch section is placed upon tiie first ono and forced 
into the mould in tho same manner. Thus sections may be added until tho desired 
50 pressure is obtained without any disarrangement of the apparatus. So powerful is 
the pressure which may be obtained by this means that cylinders of tho oxido of 
magnesium are rendered semi-transparent. 

The cylinder of oxide thus obtained is placed on a lathe and the bobbin turned 
with a cutting tool without fear of brenking. 

55 Tho electric general iug machine which I propose to use consists of a powerful 
field magnot, between tho poles of which rotate an induction bobbin. _ _ 

Tho cores of the field magnet are each three feet in length nnd about six inches 





6 A.D. 1879.—N° 2402. ,. ^ y 

Edison’s Improvements in Apparatus for Dev eloping Electric Currents, Ac. 

in diameter, and wound with a helix of insulated copper wire having a resistance 
of about ono ohm. 

Tho number of coils and the resistance of the wire may of courso bo varied to 
suit various conditions. By the uso of largo masses of iron I am enabled to reduce 
tiio resistance of the magnetic circuit to a vory low point, and at tho same timo by 5 
reason of this large mass of iron of great magnetic conductivity tho use of a singio 
layer of wire is possible, thus obtaining the maximum economy. 

Tho back or bar that connects the two cores of the inngnot is of iron, and is 
greater in mnss than in the same length of core. Tho surfneo of both the back aud 
the end of each core arc ground together, and arc permanently secured by bolts 10 
and nuts. By thus employing a largo mass of iron for the bnck, and grinding tho 
faces of contact to a point where air suction becomes powerful, I reduce the resistance 
of this point to a minimum nnd prevent the appearance of free magnetic poles. 

There aro iron poles bolted to the cores, tho surfaces being ground togother. 

Between tho two poles there is a circular aperture in which tho induction IS 
cylindor rotates. 

The cylinder may be of wood upon a shaft, and at each end of the cylinder thorn 
is n wrought iron head. 

This cylindor or bobbin is wound with fine wiro until tho wiro is (lush with tho 
edge of tho iron heads. 20 

Over this cylinder is wound longitudinally tho insulated induction wire, the ends 
of which are connected to tho commutator. Tho wiro of the purallel induction 
helix is substantially endless, and it is wound with reference to obtaining a con¬ 
tinuous current. 

The number of parallel coils may bo moro or less in number, but I find tho 25 
desired Object can be obtained by using an even number of parallel coils longi¬ 
tudinally of tho cylinder, and an odd number of the commutator plates. 

1 hero aro two insulated discs upon the shaft of tho field inngnot, nnd a metallic 
brush or spring is in contact with each disk; tho lino wires are connected to these 
disks. One end of the wire of the field magnet is connected to one disk, nnd tiio 30 
other end of the wire is connected with one of tho commutator brushes; tho other 
coiiiimitntor brush is connected with the second insulated disk. 

I lie path of the current is through one insulated disk to tho field magnet, through 
it to one commutator block, then through tho induction coil to tho opposite block 
on the commutator, and by brush and wiro to the second insulated disk, and thence 35 
to the hnc. 

The current will bo continuous, or nearly so, nnd travel in ono direction ; there 
will however sometimes bo a spark between tho commutator bars when the circuit 
ot tiio parallel induction coil is interrupted, hut this will bo lessoned by having the 
commutator springs bent to rest on moro than one commutator bar. 40 

It will be apparent that tho shell and parallel induction coil may bo revolved if 
the magnet cylinder remains stationary ; nnd I remark that the cylindor supporting 
thejminllol induction coil tnny be of any suitable material, but I prefer vulcanized 

pa ; ls of ‘ ,lis '"“Chine are not liable to become heated under ordinary eircum- 45 
USe ’ heC T e • t ’'V v,r . ea aro nofc woun< l O"® the otiier and the atmo¬ 
sphere has an opportunity to circulate. 

• f l, ‘°"' cver “Pl’iy 0 6omo instances upon tho shaft of tho field inngnot 

Lue e LT».? ra p ra -T tu,S L W L th the internal portions of tho machine, sow to 
induce a current of air through the same. 50 

tririL\vW? 1 ' t ? etofore 80 J» forth the maximum economy of illuminating by elec* 
torkhJ 3 a er - at namb , er of ^t giving points is only obtainable by 
rntiurr ° rosl ®tanoo in multiple arcs, nonce it is also necessary that the gene¬ 
rating nineinnes should also be worked in multiple arc. * 

abillM taJES* i n , U , m l’ 0r „ of , mac, ‘ in ® a in multiple arc with economy and roli- 65 
means 1 w nl1 ; 1,,,vo U, ° motive force, nnd that 

means must be devised to provent the insulating covering of tho induction bobbin 


Edison’s Improvements in Apparatus for Developing Electric Currents, Ac. 

of any machine being burned should the snmo stop for any reason, such as by the 
breaking of a belt; because if tiio wiro of tiio bobbin cease to bo tho seat of an 
electro motive forco tho current from tiio other machines pass through it and tend 
to produco sufficient bent to destroy tho insulation, and at tho samo timo cause a 
5 loss of avnilablo energy. 

I prevont any such action by the uso of n polarized magnet, which prevents the 
electric circuit boing oponed by tho direction of the flow of the current from tho 
machine whon in action tending to hold its tongue strongly against a contact point, 
but if tho machine should stop nnd ceaBO to bo the scat of an electro motive force, a 
10 current from the other machines passes through tho machine in a contrary direction, 
whoroupon tho tongue of tho polarized magnet is nttracted from its contact point 
nnd tho circuit opened. 

Koch machine boing provided with this apparatus, it is freed from tho danger 
aforementioned. 

15 An ordinury magnet with its nrmuture lever provided with a retractile spring 
might replaco the polarized magnot, but tho margin for adjustment would be very 

The resistance of tho polarized magnet is made an exceedingly small fraction of 
tho resistance of tho maoliino to prevent loss of energy. 

20 The field magnets of tho machine aro energized by supplying their helices with 
electricity from thermo-electric piles. 

Compound condensing Bteam engines are employed at tho largo control stations to 
drive the magneto electric machines, and the heat given off from tho surface con¬ 
densers acts upon thermo-electric piles to produco an electric current, and tho same 
25 is passed through the (laid of forco helices. 

The field mngnets may all he connected in multiple arc, and tho thermo electric 
piles arranged in the same manner with applinnces whereby the strongth of all the 
field may be increased or decreased at pleasure, thus increasing or decreasing tiio 
electro motive force of the induction bobbins, thus ranking it easy and convenient 
30 by the aid of electro motors at tho central stations to counteract tho rise and fall in 
the electro motive force on tho main conductors when tho maximum and minimum 
number of lamps may he working. 

I will mention tlint tho electro motive forco of the maehino is analogous to the 
pressure in the system of gas lighting nnd at dusk when the lamps are being rapidly 
35 connected to tho circuit the electro meter will shew a slight drop on the electro 
motive force or pressure, nnd this may be increased by increasing the speed of the 
prime mover or ineroiising tho power of tho field magnets; the later method is the 
one I prefer. 

The surface condensers which I omploy consists of a great number of iron pipes 
40 whose surfaces are painted with n thick coating of a non-conducting substance, lhe 
pipes after painting aro about fivo inches in dinmoter. 

Over these pipes aro slipped rings of tiio double sulpliido of lead and copper. 
Those rings are cast in a mould, and botii tho inner and outer edges are cither covered 
or platod with copper. .... 

45 Tho inner copper ring of ono disk connects with the outer copper ring of the 
adjoining disk throughout tiio ontire series of disks. . 

Owing to the exceedingly low resistance of theso disks and tho considerable 
electro motive force which they give between the low range of temperature voiy 
powerful currents aro obtained, and nearly ns much energy is thus obtained in the 
50 form of an electric current from tho wasto heat of the engmo as can bo obtained 
from the engino itself through tho medium of tho Fnradie machines. 

In British Lottors Pntent, No. 422C of 1878, granted to me, a method is described 
and shewn for measuring the total energy passing into the house of the consumer 
during a given poriod of timo, tho same consisting of a depositing cell or colls m 
65 which tiio weight of coppor deposited by tho current gives the indication. 

Instead of the cell or cells shown two cellB connected by a syphon may bo used. 

In one cell is a solution of cuprie Bulphito and a copper electrode, and in the other 










8 A.D. 1879.—N° 2402. 

Edison'a Improvements in Apparatus for Developing EUotrio Cu rrents'^. ‘ 

cell Biilpliunc acid and a copper electrode. No polaziation takes placo : the liouiti 
of the syphon tubo offers tho requisito resistance. ^ ® 

Tlio cells are sealed from tho air to prevent loss by evaporation. 

Any loss by this means may bo made good by adding wator, tho results nr» 
nearly independent of tho strongtli of the solution. b “ aro 

The central stations are intended to light an area of * of a mile in every direc- 
tion The method winch I propose to adopt for convoying the current from the 
central station to various points, consists in laying doublo wrought pipes lined 
with vulcanized rubber, known as ebonite, side'by side under tho flaggZstouL 

its? 1 ” to 10 “ '’"*•* rots U 

The pipes and box are water-tight. 

^ The top of the box, which is detachable, has its upper surface oven or flush with 
the wn kj from the same box small tubes servo to convoy wires from the ma n 
conductors to the houses of the consumers. J .. 

n J l ; e .™ rea forcing the main conductors are small, and may citlier be insulated 
and laid loosely together or insulated with a thin layer of cotton In this case each 

S coXtTfh Le ' ,d0P r° nt, ? nt - but th .° «*«»* is greater when Urn whesare 
c ? n taot, as then when few lumps are in use the resistance of tho main con¬ 
ductor is relatively small as compared to tho lamps. , n 

1 lie Prance of causing the total resistance of the circuit extraneous to the 
obtained 1, from th q 0 U mad,'n at -° f ^ e " n ®“‘? r ' “ nd b y whiol > the maximum effect is 

£25 a.TttRslt 25 

lated, owing to the changed conditions, 80 per cent, may be utilized 


pAdfleaUon. A.D. 1879.—N° 2402. ( 

Edison’s Improvements in Apparatus for Developing Electric Currents, £o. 


SPECIFICATION in pursuance of tho conditions of tho Lottors Patent filed by 
tho said Thomas Alva Edison in tho Croat Seal Patent Oflico on the 17th 
Dccembor 1879. 

Thomas Alva. Edison, of Menlo Park, in the State of Now Jersey, United 
5 States or Amonca, Eloctrician. •* Improvements in Electric Lights and in 
Apparatus for Developing Electric Currents and Regulating the Action 

OP TnE SAME. 

I havo ascertained that when wires or slioets of platina, iridium, or other 
inotallic conductors of electricity whicli fuse at a high temperature aro exposed to a 
10 high tomperaturo near their molting point in air for several hours, bvpassin" a 
current of electricity through them, and then aro allowed to cool, the’ metal is found 
to bo ruptured, and under tlio microscope there is revealed myriads of cracks in 
cvciy direction, many of whicli are seen to reach nearly to tho center of tho wire 

I have also discovered that contrary to the received notion, platinum or platinum 
lo and iridium alloy loses weight when exposed to the heat of a candle, that oven 
heated air causes it to loso weight, that the loss is so great that it tinges a hydrogen 
flame greon, and under the influence of an olectric current and nt a yellow white 
heat the loss is very great. After a time tho metal falls to pieces, hence wire or 
sheets of platinum or platinum and iridium alloy as now known in commerce are 
.0 useless for giving light by incandescence, 1st., because its loss of weight makes it 
expensive and unreliable, and causes the burner to be rapidly destroyed. 2nd 
becuuso its electrical resistance changes by loss in weight and its light giving 
power by tlio cracks or ruptures, tho melting point being determined by the 
u . we “kcst spot wliore tho greatest difference of potential of the olectrio current is 
-a present which causes this point to be brought to a higher heat than the rest of tho 
surfaco of tho wire. Again, as it is essential to obtain a steady light the platinum 
burner must bo screened from tlio air, and when thus scrconcd by boing placod in a 
glass vessel, tlio glass soon becomes coated with a black deposit of platinum. A 
platinum spiral brought to incandescenco under tlicso conditions may be made to 
30 give a light of tlireo standard candles when nenr its molting point, and when the 
radiating surfaco is s / M of an inch, but this amount of light will bo rapidly reduced 
as bofore described. 

From my researches and experiments I am led to beliove that tlio cause of tho 
rupturing of tlio metal when brought to incandescence is duo to the action of the 
35 gases contained in the pores of tlio metal. Tlieso gases aro probably compressed 
within tlio pores during the rolling or drawing of the sheet or wire. These gases 
or air when subjected to high heat are greatly expanded and rupture tho metal, 
and it cannot bo driven out by slowly heating tlio metal. 

I novo also discovered that tho loss of woight and apparent volatilization of tho 
40 metal is duo to the action of tho air or gases against the highly boated surfaco. 

Haying thus nscortninod tho cause of fracture and loss of woight, I have conducted 
experiments to obviate these dofects and havo succeeded by tho following mothod. 

A spiral of platinum wire is placod in a glass bulb with its onds passing through 
, spbied in tho glnas, and the air oxlmusted from tho bulb by a Sprengel pump until 
45 the discharge from a three incli induction coil will not pass between two subsiduary 
wires in tho bulb, tho onds of which are four millimetres apart The wires of tho 
spiral aro then connected to n magneto electric machine or battery whoso current 
ean bo controlled by tho addition of rosistanco. Sufficient current is allowed to 
pass through tho wire to bring it to about 150° Fall., it is allowed to remain nt this 
tomperaturo for 10 or 15 minutes. Whilo thus heated, the air or gases in the pores 
ot tho metal are expelled by tho action of tho boat and tho expansion of tho gases 
W \VI*i Cnd to pass outward in consequence of tlio vacuum. 

While the air or the gases are passing out of the metal the merourv pump is 




_ Edis on's Improvements in Appara tus for Developing Electric Currents, Ac. 

kept continuously working. After tlio expiration of about fifteen minutes the 
current passing through the metal is to bo augmented so that its tompemturo will 
bo about 3011° Falir., and it is allowed to remain at this temperature for another ton 
or fifteen minutes. If the mercury pump bo worked continuously, and the 
temperature of tlio spiral raised at intervals of ten or fifteen minutes until it nttaius 5 
vivid incandescence, and the bulb be then sealed, the metallic wire is then in a 
stato heretofore unknown, for it may havo its tompemturo raised to the moat 
dazzling incandesconco, emitting a light of twonty-fivo standard candles, whereas 
before treatment the same spiral would only omit a light equal to three candles 
beforo attaining the melting point. The wires subjected to the process of freeing 10 
them from air and gases aro found after the process to huve a polisli oxccoding that 
of silver, and attainable by no other means; no cracks can bo seen even after tho 
spiral has been raised suddenly to incandescence mnny times by tho current, and no 
volatilization takes placo as there is no deposit upon the glass bulb, nor does a 
delieato balance shown any loss of weight in the spiral, even aftor said spiral has IS 
been burning for many hours continuously, because tlio spiral is in a vacuum so 
nearly perfect timt the action of the gaseous molecules is reduced to tho minimum, 
and were it possible to obtain an absolute vacuum there would bo no loss 
whatever. 

I have further discovered that if an alloy of platinum and iridium, or even 20 
platinum, be coated witli tho oxide of magnesium in tho manner hereafter stated, 
and subjected to tho vacuum process described, that combination takes place between 
the metal and the oxide, giving the former remarkable properties. With a spiral 
having a radiating surface »/,„ of an inch, light equal to that given by forty standard 
candles may bo obtained, whereas tho snmo spiral not passed through my process 25 
would melc before giving a light of four candles. Tlio offect of the oxide of 
magnesia is to harden tiie wire to a surprising extent and render it more 
refractory. 

A spiral spring niado of tho wire is as elastic and springy when at dazzling 
incandescence as when cold. 30 

I have found that chemically pure iron and nickel drawn in wires and subjected 
openair aCUUm 1>r0 ° e33 may 1)0 lnade t0 6 ivo “ Rg bt equal to that of platinum in the 

Carbon sticks may be also freed from air in this manner aud bo brought to a 
temperature that tlio carbon becomes pasty, and if then allowed to cool is venr 35 
homogeneous and hard. Rods or plates made of mixtures of finely divided con¬ 
ducting and non conducting materials may thus be freed from air. 

It is also obvious that tho metal might bo heated by subjecting tho containing 
bulb to a considerable temperature, but this only partially frees the wire from its 
air or gases. 40 

I will now describe tlio form of burner or lamp which I employ. To oporato 
several hundred electric lamps practically, each equal to an ordinary gas jet, upon 
one circuit it is essential for many reasons, both on tho score of economy, facility, 
and reliability to place thorn all in multiple arc, and to prevent the combined 
resistance of several hundred lumps from falling to such a low point ns to require 45 
main conductors of immense dimensions witli low resistance, and generating 
machines of corresponding character, it is essential to reverse tho present and almost 
universal practice of using lamps which shall liavo but ono or two ohms resistance, and 
construct lamps which shall havo, when giving thoir proper light, a resistance of several 
hundred oluns, because tho more lamps there aro in tho circuit tlio less will bo the 50 
resistance. I have ascertained by experiment that tho loss of onorgy is in propor- 
'° n , to . t l0 . exte,lt °f t* 10 radiating surface independent of tlio resistance of tho 
conductor ; hence we havo 1,000 lamps, each of 1 /, of an inch radiating surfaco, and 
1*000 f| 0n ° °‘™ rcsiatunce , or 1,000 lamps having the samo radiating surfaco and 
liZ n/m rCS '“ Un n 0 0, ‘? !■ 11,0 loss of “orgy from each lamp when giving each a 65 
one Ohm 1 r “ m "' 1 ", bo "e Car| y tlie Sluue - but t,le combined resistance of tho 
m laTnpg will be of an ohm, requiring an enotinoiifl main conductor, 


ip»in<uiion. A.D. 1879.—N° 2402. 11 

Edison’s Improvements in Apparatus for Developing Electric Cu rrents, &e. 

whereas tlio combined resistance of tho 1,000 ohm lamps will bo ono ohm, requiring 
a conductor of very moderate dimensions. In praotico a resistance of 200 to 300 
ohms in tho burnor will bo sufficient. Again, with lamps of low resistance tho lamp 
connections and loading wires must bo largo to provont great loss of onorgy bv 
5 resistance; the leading wires from the main conductors are large, expensive, and 
bulky to handle; tlio low rosistaneo of tho burner or incandescent conductor requires 
laigo terminals to convoy the curront, and these officr by thoir conduction a medium 
for tlio rapid dissipation of onergy without producing any effect, whorens with a 
lamp of high rosistaneo all these objections aro obviated. 

10 My burner 6 consists of a bobbin composed of an infusible oxide, such as oxide of 
calcium, corium, zirconium, magnesium, freed from silica and turned in a lntho from 
sticks molded by hydraulic pressure in a manner hereinafter sot forth, and upon this 
bobbin fine wiro of platinum or platinum-iridium alloy is coiled. This bobbin is 
shown in Fig. 1; it is secured to two platinum wires 1,2, as in Fig. 2. These wires 
15 servo to hold tho bobbin in tho conter of tho sealed glass vacuum bulb, and at tho 
saum time Bervo ns conductors of tlio electric currant to tho wiro coiled upon the 
bobbin. Fig. 3 shows tho manner of connecting tho wiro upon the bobbin to the 
platinn supports. Tho two platinn wires 1, 2, nro first passed through a small tubo 
a of glass, and tho glass melted around the wires. Tho burnor b is introduced into 
20 the bulb c, nud the wires 1 & 2 are passed out through tlio sides of the narrow neck 
loading from tho bulb,and tlio glass is melted around them to prevent leakage; tho 
glass of the neck is melted to tho small gloss tube a. Before tlio burner is perma¬ 
nently scaled at tho nock the air pump is connected therewith and tho wiro upon 
the bobbin is subjected to tho vacuum process heretofore described, and tlio electric 
.5 current is used to produce incandesconco for about ono hour to heat tho bobbin, and 
thereby expcll the air nnd gases, after which the bulb is permanently sealed by 
melting tlio glass of the neck, aud it is ready to bo used ns a lamp, as represented in 
rig. 4. 

The method which I adop for regulating the light radiated from tho burnor 
30 consists in _n smnll rotating magnet provided with a governor, which serves to open 
the lamp circuit when tho strength of the current is greater than is necessary to 
produce tho proper light in tho bobbin. This apparatus is very reliable, and 
although tlio current supplied is not perfectly continuous tlio total energy passing 
to tho lamp in ono hour is nearly the same, no matter what the current strength 
35 may be, tho magnets being so arranged that tho continuous metallic circuit cannot 
bo broken by the commutator of tho revolving magnet, and tho extra current 
produced by tho reversal of tho current in tlio revolving magnet is short circuited 
by tlio fixed magnet, lienee tho sparks which would occur at tlio break-points of tlio 
in !> < ! 1 J? mo r “ ro prevented. Referring to Fig. i, b is tho bobbin with tlio platinum 
40 indium wiro which forms tho electric lamp, c is tlio sealed glass bulb; f and g are 
supports to hold the bulb in position; tlieso aro insulated from each other. Tho 
platinum wires 1 nnd 2 from tho bulb are connected to these supports. 

.. *• ' •» » box for supporting the lamp and enclosing tlio governor; n is the back of 
the fixed magnet, consisting of tho spools o, o 1 ; p, p', aro tho spools of tlio revolving 
4a magnot; r is tho back of tho samo, which is secured permanently to the shaft q, 
upon which is a revolving commutator s. This commutator consists of a ring of 
insulating material, whoso periphery is faced with platina and cut in two parts, 
one part being connected by tho wiro 5 to tlio magnot p\ nnd tho other part by 
50 to tl'* 0 * 10 tbo 1,m fi not P‘ Tlio wire 05 connocts the two spools p aud p l 

Rubbing on this ring aro two contact springs s l , <*, which Bervo to convey the 
currents to tho revolving magnet. Tlio current'passes through the fixed magnot 
°> o', see diagram Fig. 6; tlionco by wires 4, 5, springs s', t l , through the revolving 
magnet p, p\ Tlio rotation of tho magnot is kopt up by the reversal of tho direction 
a of the flow of the currents through tlio revolving magnet. Whoa tho cores of tlio 
revolving magnot arc nearest the cores of the fixed magnet tho direction of tlio 
current through the former is reversed by tlio action of tlio springs s', t', upon tho 






12 A.D. 1879.—N« 2402. nwiuta; 

Edison'8 Improvements in Apparatus for Developing Electric Currents, <£•«. 

commutator and the polarity changed, honce the attraction ceases; but the 
momentum of tho magnotp, p*. carries it forward, and mutual attraction again takes 
place j ns tho revolving cores approach the stationary coros tho current is reversed 
and tho revolution continued. 

Connected to tho revolving shaft q is the govornor, which consists of two collate 5 
v, w, connected by springs C & 7, the collar V is permanently secured to the shaft, 
while tho collar w is free to slide up and down upon it. Each spring is provided 
at its center with a weight, and those weights act centrifugally to bow outwardly 
the springs and raise the collar w upwardly more or less in proportion to the speed 
of revolution. Connected to to by a sleovo is another collar 19, upon tho surface of 10 
which rests tho end of the circuit opening levor l, which rises and falls by tho 
action of tho governor. A spiral spring P, see Fig. 5, on tho axis of tho lover { 
servos to keep l in contact with 19. Upon tho extreme end of the lover i is a 
block 18 in juxtaposition to circuit breaking springs 8 & 9, and serves to disconnect 
tho springs simultaneously from tho metallic block 10, when the governor nnd 15 
shaft has reached a certain velocity. Tho block 10 is insulated from tho frame 11, 
and serves to keep the circuit closed betwcon the springs. 

The current passes by wire 81 to tho spring 8, tlionce across the block 10 to tlia 
spring 9, thence to tho magnet and lamp by wire 85. 

The object of employing two springs is to open the circuit in two places Bimul- 20 
taneously and thus reduce the spark, which it does in the ratio of tho square of tho 
number of simultaneous breaks. This method of breaking tiio circuit simultaneously 
in many places is applicable to all kinds of electrical apparatus where largo nnd 
powerful sparks occur; ns for instance, ifit is desired to transfer electric enorgyfrom 
one point to another by dynamo electric machines, tho distant machine, which serves 25 
to give out tho power for driving machinery, may bo provided with a governor tho 
same as herein shown, and the circuit may bo opened in several places simultaneously 
by tho action of tho governor shown in Fig. 0. I is tho lover operated by tho 
governor; 12 nnd 13 are contact springs, which rest upon tho bar 43 ; 14 nnd 15 
are also contact springs which rest on the bur 44. Tho current passes by wire 84 30 
to spring 12, across tho bar 43 to spring 13, tlicnco by wire 45 to spring 14, across 
bnr 44 to spring 15 to wire 85. When the govornor reaches a certain velocity tho 
insulated piece 18 of tho lover l comes in contact with all the springs simultaneously 
and separates them from tho bars 43 & 44, thus opening the circuit in four places 
simultaneously, the spark is reduced to 1 / u of what it would be if a single break 35 
was used. Having shown the importance of breaking tho circuit simultaneously 
in many places I will now describe how the illumination of tho burner b may bo 
increased or decreased, or stoppod entirely. 

Referring to Figs. 4 & 6 t is tho thumb nut for regulating tho speed of tho 
revolving magnet and consequently the amount of energy which posses to the 40 
burner. The nut 22 is provided witli a slot or groove containing a stationary 
pin p 1 , and into the nut 22 the screw 20 passes, and by turning this screw tho 
block 10 may bo drawn inwardly or forced outwardly, said block running on two 
guide pins 23,24, which prevent the block from turning; tiius tho block 10 may bo 
made to approach or recede from tho levor l. 45-' 

. ^ 'desired to turn off the light nnd disconnect tho lamp altogether from tho 
circuit, the screw is turned to tho right until tho block 18 separates tho springs 8 
& 9 from tho block 10 and opens tho circuit. In this position tho circuit is broken 
and the lamp and magnets are entirely disconnected from the circuit. 

If it is desired to have the lamp give light tho screw is turned to the loft; when 60' 
the springs 8 & 9 come in contact with tho block 10 and close tho circuit, tho 
magnets immediately revolve; and if the parts are left in such a position that the 
piece 18 is in close proximity to tho springs, tho rotation of tho magnet willopornto 
the governor nnd lesson the pressure of 8 nnd 9 on 10, and hence the speed will bo 
comparatively slow and tho electricity passing to tho light will bo vory small and 55’ 
but httlo light will bo given out, but by causing tho block 18 to further recede 


Edison's Impro vements in Apparatus for Developing Electric Currents, £o. 

from 8 & 9 tho speed of the magnet will increase and more energy will pass to tho 
lamp in a givon timo. 

By continued turning of the screw 20 a point may bo reached where tho 
governor lover l will not soparato tho springs 8 & 9 from 18; in this case tho entire 
6 electric enorgy passes through tho bobbin b, but in practice limiting stops are 
applied so that when tho screw has been turned a certain distanco the further move¬ 
ment will bo prevented by tho action of tho stops, thereby determining the 
maximum light which tho consumer can obtain from tho burner. In practice this 
will bo about sixteen candle power, the burner being capable of giving thirty fivo 
10 caadlo power without fusion. 

As there may bo a point where tho revolving mngnot after being at test will not 
start when tho current is put on I use an automatic starter which consists of a light 
lever nnd thin armature turned edgewise which is attracted by tho fixed inagnot at 
the moment tho current is put on. Tho liiovoniont of this lever which carries upon 
15 its end a click servos to givo a sudden motion to the shaft q by the click engaging 
in n ratchet or toothed wheel which is secured to it. The click uftor this move¬ 
ment passes beyond tho ratchet and does not come in contact again until the magnet 
is stopiied and tho current is broken. 

In the Specification of my British Patont, No. 5300, of 1878,1 have described 
20 tho manner or coating the wire witli pyroinsulnting material; I employ that mode 
in coating the wire after which a coil of said wire is wound upon ono or more 
bobbins and placed in a sealed bulb, and connected to a vacuum apparatus, and by 
gradually increasing the heat of tho wire by tho gradual rise in tho current strength, 
as described in the first part of this Specification, tho wire is not only freed from 
25 air nnd rendered more refractory, but the oxido is vitrified nnd shrinks upon the 
wire from which it cannot be detached. The coil after passing through this process 
may be wound upon the lime bobbin of the lump without fear of breaking the 
pyroimulation. After the bobbin is wound and placed in tho final bulb any air 
which may have passed into tho oxides is expelled by a gradual accession of current 
30 in the manner heretofore described, and the bulb is then sealed. Tho oxides of tho 
alkaline materials which aro infusible attack tho platina to a slight extent and 
adhere with greater tenacity to it than tho oxides which do not attack it, such as 
ceruin or zirconium, but tho compound thus formed renders the u’iro more refractory. 
It is not essential that tho oxide should be in tho form of a soluble salt, as it 
35 may bo put on tho wire directly by mechanically mixing the oxido with wntoi, 
alcohol, or other liquids, but special devices nro required to keep tho mixture in 

™,a .i«i„ **.* .h. T k. ;: t 

on account of tho bending and breaking of the plunger of tho mold, which owing 
40 to the pulverulent nature of most of tho oxides must bo long and 

I have obviated this difficulty by devising a mold and plunger by which pressures 
to the crushing point of steol may bo concentrated upon one quarterret an in.ill 
surface. Tbisapparatus is applicable to the molding of any substo, ce.amli s 
shown by a vortical section in Fig. 7. Fig. 8 is a plan of the divided mold, a is 
45 the plunger; upon the extreme end is tho part d* wh'c' o n tora tho d le o nold. 
This is o?ily about ono quarter of an inch long and about three eighths of an inch 
in diameter, and it is adapted to pass downwardly into the mold. 

* is a solid block of cast iron* with a taper hole in its conter, nnd into fo.s tho 
divided steel mold/* is forced; this mold is mode of three pieces 
50 tnpor as tho holo in tho block c 2 . The object of the taper and div dod mold is to 
allow tho pressed piece to bo taken out without tho injury it would reeeivo wore 
it forced out of the mold endwise. After tho mold has been faded o tlie op w th 
tl.o pulverulent oxido a steel washer or plunger section h- is' P" 00< * u P on ll ‘° ?* 
and* forced into tho mold by tho plunger; afterwards ..nothe. “ 

55 placod upon tho first ono and forced into tho mold in the “ without anv 

sections may be added until tho requisite pressure is obtaiued without a y 



•14 A.D. 1879.— N° 2402. 

Edison's Improvements in Apparatus for Developing E lectric Currents, <fo. ~ 

disarrangement of the apparatus. So powerful is tlio pressure which may bo obtained 
by this means that cylinders of tlio oxido of mngnosiinn nro rendored semi 
transparent The cylindor of oxido thus obtainod is placed in a latho and the* 
bobbin turnod with a cutting tool without fear of breaking. 

Tlio electric generating machine which I propose to uso consists of a powerful s 
field magnet betweon the poles of which rotate an induction bobbin This 
apparatus is shown by a vortical section in Fig. 0, and sectional plan Fig. 10 F i 9 
tlio field magnet, tlio cores of which nro about threo foot in length and tlio 
dinmetcr about six inches, wound with a helix of insulated copper wiro having 
a resistance of about ono ohm. Tlio number of coils and tlio resistanco of 10 
tlio wire may of course be varied to meet various conditions. By tlio uso of 
largo masses of iron I am enabled to reduce tlio resistance of tlio ma^notic circuit 
ton very low point, and at tlio same time by reason of this largo “mass of iron 
of groat magnetic conductivity tlio uso 0 r a single layer of wiro is possible, thus 
obtaining the maximum economy, a? is tlio back of tho magnet and the mass of 15 
iron is greater than in tho samo longth of core. The surfaco of both the back and 
the end of each core are ground together and nro permanently secured by bolts and 
nuts. By thus employing a large mass of iron for tho back and grinding the faces 
of contact to a point wliero air auction becomes powerful, I reduce the resistance 
of this point to a maximum and prevent tlio appearance of freo magnetic polos- 20 
a, a, are iron poes bolted to the cores, the surfaces being ground togothor.’ 

rntr en Tl? t ' V r , 1 '! lc V' 1 . cre 18 r T ulai : a P°'' t,,ro in wllich tbo induction cylinder 
lotatco. The cylinder It is preferably of wood upon tho shaft b\ and has wrought 
iron heads b . This cylinder is wound with fine iron wire 6° until tho wire is 
flush with the edgo of tho iron heads b\ Over this cylinder is wound longitudinally 25 
the insulated induction wire in sections, the ends of which are connected to the 
commutator % as in Fig. 11. There are heads <f> of hard rubber, vulcanite, fiber, or 
eqmvalent material secured to the shaft b\ see Figs. ICand 17. outside the heads Id, 

I „n " S r S ° tlmt tl,e .induction wires c‘ that are wound longi¬ 

tudinally may be kept from contact with the iron helix ¥ or heads ¥, so that 30 
tlio current may not bo short circuited even if tho insulation of tho induction wires e* 
Whi'cif H 18 II . for dri Y"!e tho ,nao hino ; c° is a looso pulley upon 

to bo stopped 8 1 iS ttaown by a allifter wIlG “ tho machinois 

onenod ? Ind ca y i . s w *iich t * 10 circuit from the Faradic machine may be 33 
in the til;? 1-T th ° co, T utat ? r spring 8 i A’ is a polarised magnet included 
in the circuit, which serves automatically to onen thc cimi.il n i„„iu n 


ton cue WLV ? f 8 ' y s i T r I3 , ln contaot with thence through the 

uron tlm fiehl L1F° ‘ ^ t , hr0Ue 1 tho mn 8 not # t0 kllc P«st A». The wiro 
describe the n.cM g l r 1S ?T ecte ? l ? a '° clomping posts P and l>. I will now 
currentf mla ^ wlndln g «>o induction cylinder and tho direction of tho 
bel « « e commutator brushes :-The wiro of tho parallel induction 45 

tinuo, current and lfc n . is Y v , 0H " d with ^ferenco to obtaining a con- 

wires- the num'hm- nf n dl j’.S lam > -Hlg- 1 •» illustrates tlio manner of winding the 
find thc oldr i ? ^ , “‘l 8 , ? ay , be moro or 1( =ss than that shown, but I 

°.,J 0Gt demied can be attainod tho best by using an oven number of 
Star inc'sav frem‘tU™ T ,° f tb ° shaft < and ™ odd /umbe^of commutator plates. 50 
on ine tad y :/ra^l ^ 1 ° f tho c ? m,nutat or, tho wire posses to tho space 4 
space 11 and to the . " m ° 8| ’ aC0 tlle otllcr '"' ad . across tho head to tho 
p^oi 'and so n° r?r° 0 ° n th ,° olhor ,load - f'cs across tho head to tlio 
the last turn in 11 l.na h th ,°.5 l 2 e “ * n “ d 11 ar0 dll ° d with tho wire, and when 
2 and 9 are filled andl^?" th °' vi ! e is , ledto P^te c, and then tho spaces 55 
* anu u aro filled, and the wire from 0 led to d j then 14 and 7, and a connection made 


6*rfMon. A.D. 1879.—N° 2402. :15 

Edison’s Improvements in Apparatus for Developing Electric Currents, Ac. 

with e ; then 12 and 5, connecting with /; then 10 and 3, connecting with g j then 
8 and 1, connecting with a ; then C and 13, connecting with 6, tho place of beginning. 

1 wind tho wires in such a manner that while the current is continuous, and the 
current flowing through tho whole of it, tho current will pass by two wires of the 
6 induction coil to ono commutator pinto, and then away, and will enter by an 
opposite commutator plate, and pass by two wires out into the coil, and circulate 
through the samo to the other commutator plate. Suppose tho springs to rest upon 
commutator plates a and o the current will flow towards a from wires 1 and 6, 
and away from c by wires 12 and 7. By following tho arrows it will be found that 
10 tho entiro coil is a complete circuit, in which tho parallel portions of tho wires in 
the south field of magnetic influonco Imvo a current energized in ono direction, 
and in tho north fiold in tho other direction, thus obtaining tho dynamic effect, 
and there is no break or pulsation of tlio current; tho springs touch ono com¬ 
mutator before loaving another. 

15 As I have heretofore set forth, the maximum economy of illuminating by 
electricity when using a great number of light giving points is only obtainable by- 
working the resistanco in multiple arc, hence it is essential that the generating 
mnehines should also bo worked in multiple aro. To work a great number of 
machines in multiple-arc with economy and reliability, it is essential that all should 
20 have the samo electromotivo force, and that means must be devised to provent 
injury by burning, to tho insulating covering of the induction coil of any machine, 
should said machine stop for any reason, such as by the breaking of a belt, bccauso 
if tho wiro of tlio induction coil ceases to be the seat of an clectro-motivo force, tho 
current from tho other machines pass through it and tend to produce sufficient heat 
25 to destroy the insulation, and at the saino time enuso a loss of available energy. 

I prevent any such action by tho uso of the magnet Id, Fig. 10, which being 
polarized, is prevented from opening the electric circuit by the direction of the flow of 
current from tho machine when in action, tending to hold its tongue strongly 
against tho contact point i s ; but if tlio machine should stop and cease to be tlio 
30 seat of an electro-motive force, a current from the other machine tends to pass 
through tho machine in a contrary direction, whereupon the tongue of Id is detached 
from the point i 5 , and tho circuit opened. Each machino being provided with this 
apparatus is thus freed from the danger described. An ordinary magnet might 
replace the polarized ono, and a retractile spring used, but the margin for ndjust- 
35 ment would be vory small. . 

Tho resistance of the magnet Id is made an exceedingly small fraction of the 
resistanco of tho machino to provont loss of energy. 

Tho field magnets of the machine aro energized by supplying tliom with electricity 
from thermo electric piles. 

40 Compound condensing stenm engines aro employed at tho largo contral stations 
to drive the magneto electric mnehinos, and tlio boat given oft by the surfaco con¬ 
densers net upon the thermo olectric piles to produce an electric current, and the 
same is passed through tho field of forco helices. 

Tho field magnots may all bo arrangod in multiplo arc, and the thermo electric 
45 piles arranged in tho some manner with appliances, whoroby the strength of all 
tho field magnets may bo increased or decreased at plonsure, thus increasing or 
decreasing the electro motive forco of tho induction bobbins, thus making it easy 
and convenient by tho aid of eloctroniotors at the central stations to counteract 
the rise and fall in tho electro motive forco on tho main conductors, when the 
60 niaxiinum and minimum number of lamps may bo working. 

I will mention that tho electro-motive force is analogous o the pressure in the 
system of gas lighting, and at dusk when tho lamps nro rapid y being connected to 
tho circuit, tho olectrometer will show a slight drop on the eloctro motive force or 
pressure, and this may bo increased either by increasing the Bpeod of the prime 
55 mover, or an increaso in the powor of tho fiold magnets, the latter inothod is the 

Tho^surfaco condonsors which I employ consist of a groat number of iron pipes 







16 A.D. 1879.—N° 2402. aped4cula 

Edison's Improvements in Apparatus for De veloping Electric Cwrents. £o~~ 

whoso surfaces are painted with a thick coating of a non-conducting substan^ 
"J'l- aft ° r Pointing aro about fivo indies in diamotcr. Over theso 8 nro slipped 
a Tl,otl 1 t *b 0 d i , n„ b ! 8ul ! ,lud .° of , lead nnd . f°PP°«-. These rings arc cast in a mold, 

F dl ,o fnd in La - d °, utor . cd e° s a ™ , eltI > er covered or plated with coppor. In 
Fi s, 1- am 13, m is the ring or disk of doublo sulphide; m 4 , tho copper rim? 5 
^ 0< o n t s e i ‘ 0 0 „° m ,i 1,1 f pp . 0r rin S whie!l ovc tho circumferonco of * 

m , to tins l ing a binding post and strip or wire m° is secured, tho latter to connect 
to the next disk. m< represents one of the condensing pipes. 

of “i eonnectslo’the a current - Tl, ° inner copper 

So motivL g foLe ivbich th ing ^ of ^"o disks" «■“ Z cm.sidembk 10 

current m ,oldained ^nd I’? f‘ Ve fc T n ! ° W rnI 7 8es of 1 temperature, very powerful 

? UB P 011lts consists in laying double wrought pipes, lined with vulcanized 
S ™etlk n0 lL a : ) it 0 a , t'| i<1 , 0 b ^; d0 U ( nde / «*? «ng g in g «to’nes near tht edgooftfm 
aranlmvT 1 ^ jV" twenty foet len = tlls ' tho four ends passing into a 20 

instead of actingns paS ofonem„fa ^ wireS * 

by beine coated with a con J tuctol » *J re to bo insulated from each other 

i *» 

fat, »" bf«o"f bi" r’.T r ” " f . “V. twenty or twn.ly lira j« 

tlie lino of pipe for drawing the w°re ZouT bac p kwnrd . and through 35 

cover c which is bolted in ° , e ^ lre through each suction. Tho box has a 

between tho top and the W-T** S ° ft r “ bbor or oiltd leather washers aro placed 
insido of the bo P x and covt L toZT, a,r ^^cr leaking into the box. The 
waterproof material. One end of the svs^m ' vdh , cbo " lto or . other non-conducting 
and if the other ends nrn i * 18 syster of tubes passes into tho central station, 40 
of pipes ^this wiil nromote £ “ "‘7 b ° produced "’ithin the whole system 

into the pipes but the vnoum vnpmation ot any moisture which may have passed 
pass into P Straf fc tti:L “iL ^ b ° » the twS ends 

prevent dampness. In the L i f? b ?. P“ acd through occasionally to 

employed on each side of tho street buMbI» Ctn0 i 6 ' 1 "' 8 two lincs of P'P CS al '° 45 

boxes. I prefer that both li„»J !r • 1 may bo separate and have independent 
nested to one range of bo« a •i?’ P f 8 ° n , C 'J cl ‘ sido of tbo street should be con- 
witl. rubbers connected at r^h? ' U ? 8t ? l °.? io *!* «• A small pipe s insulated 
the boxes into tho liouso to bn^lhiL*'® 03 ,° tb ® ,nal !‘ P‘P CS . “nd passes from one of 
made of one or more wires p- bani , 1 ?' lce 1 l J’ nnd carrlos the conductor, which may bo 60 
serves to carry tho second » .t° i r m,un conductor another small tubes 
through tbo meter aro carriiTiLt 4 ° t '° l0U8e ' -^eso wires, entering the liouso 
in multiple arc between the tivn'^Ti 1 " 083 10 ? IUB, . and 1,10 electric lamps connected 
and, as mentioned nLv o,Llv Ln„ T i° WC ? fo ™ in S tlle main conductors aro small, 
insulated with a thin iaver ofcotton b ? u ^ ln8ulate “ antl laid loosely together, or {5 


spdAauioa, A.D. 1879.—N° 2402. 17 

Edison's Improvements in Apparatus for Developing Electric Curnnts, die. 

then, when fow lamps aro in uso, the reBistanco of tho main conductor is relatively 
■mall as compared to tho lamps. Tho practico of causing tbo total resistance of tbo 
circuit extraneous to the generator to bo equal to that of the generator almost 
universally prevails, nnd by which tbo maximum ofiect is obtained, is vory wastoful 
5 of energy, for by thus arranging tho resistances fifty por cent, of tho onorgy is lost 
in the maciiino itself, whereas if the exterior resistance is four times greater than 
the maciiino tho capacity of tho machine to translate energy from ono to tho other 
is lessened, but of what is translated, owing to tho changed conditions, eighty per 
cent, may bo utilized. For this reason I so arrange the resistance of the main 
10 conductors that thoy should bo but one tenth of tbo total resistanco of all tho lamps, 
and tlio resistance duo to tbo generating machines is kept down by keeping in 
multiple are a greater number of machines than iB necessary to supply all the lights 
which may lmppcu to be in circuit at tho timo. 

I claim ns my Invontion,— 

15 First. Tho combination with a sealed vacuum chamber made of a glass vessel of a 
continuous incnudcsccnt conductor wound upon n bobbin of infusiblo material, 
substantially as set forth. 

Second. The method herein described of preparing metals and metallic conductors 
for electric lamps or burners, consisting in freeing tho metallic conductors of gases 
20 in a vacuum, nnd then hermoticnlly sealing the surrounding air tight transparent 
case, substantially as specified. 

Third. In an electric lamp, tlio combination with a sealed transparent vacuum 
esse of a bobbin of pyroinsulated wiro wound upon an infusible substanco, 
substantially as specified. 

25 Fourth. In combination with an electric light and tbo circuits thereof, two oleotro 
magnets, ono of which is caused to revolve, a governor operated by tho spoed, and a 
circuit regulator controlled by the governor, whereby tlio uniformity of tbo current 
passing to the light is maintained, substantially as sot forth. 

Fifth. In combination with nil electric light, nit adjustable circuit regulator 
30 composed of the insulated springs connected witli tlio circuit wires, a contact block 
upon which said springs rest, and a governor lover l to regulate the pressure of tho 

contact springs upon the contact block, substantially as set forth. 

Sixth. Tbo process of molding sticks of pulverulent material, consisting m filling 
the mold with tho material to be compressed, and then compressing tbo mass by 
35 successive operations by means of a plunger nnd plunger sections, substantially ns 
described. , , 

Seventh. Tho divided mold f nnd block c- in combination with the plunger a 

and plunger sections A 8 , substantially ns and for the purposes set forth. 

Eighth. Tlio combination in a ningnoto electric maciiino of the helix of wire b 
40 and the wires e 4 , wound and connected to tho commutator blocks z 4 as described, and 
formirg a parallel induction coil that occupies tlio space and revolves between tho 
poles of the Sold magnet, substantially ns set forth. 

Ninth. Tlio combination in a magneto electric machine of tbo magnetic cylinder, 
composed of tlio liolix b” surrounded by tbo parallel induction coil e , and revolving 
45 between tbo poles of tbo field magnot, tho commutator %*, springs il nnd d , and 
circuit connections, substantially as set forth. , . 

Tenth. In a magneto olectrio machine, a parallel induction coil, tlio wires of which 
are wound substantially as shown in Fig. 11, and commutator connections to tho 
wires, whereby tlio current is tnkon off from tiie parallel induction coil at two points 
*0 in opposite directions, substantially as set forth. . . . 

Eleventh. Tlio cylinder 6 5 , of wood or similar material, with tbo iron beads 
1‘ and intervening holix of wiro 6° in combination with tho disks e 3 of non- 
conducting material, nnd tlio induction helix c 4 wound lengthwise and into notches 
in tlio edges of tlio insulating disks, substantially ns sot forth. 

56 Twelfth. A polarized electro-magnet in the multiple are circuit of the magnate 
electric maciiino, for opening tho circuit to the machine to which it is connected in 
Paso of dorageinent of said machine. 




A.D. 1879.—N° 2402. 


Edison's Improvements in Apparatus for Developing Electric Current a, <fo. 


Thirteenth. The thormo-olcctrio piles, connected ns sot forth upon tho condonsing 
pipes of nn engine, iu combination with tho magneto electric machine, substantially 
as sot forth, 1 

Fourteenth. Tho combination with tho electric conductors M of metallic tubes 
nnrl i<«wi ™H,o,. w.. similar non conducting substanco, substantially as sot 


lined with hard rubber 
forth. 

Fifteenth, Tho metallic tubes lined with non-conducting material, such os hard 
rubber, in combination with motallic boxes B lined with similar material, and 
uniting tho tubes and tho conductors pnssed through such tubes, substantially as sot 


Sixteenth. An induction bobbin nenrly surrounded by tho poles of tho field M 
magnet, and tho combination therewith of an abnormally large fiold magnet, which 
shall be in proportion to tho size of tho pole-pieces, ns described, for obtaining a 
powerful electro-motive forco in the wires of tho revolving bobbin without great 
loss of energy, as set forth. b 


Witnesses, 

S. L. GniFFW, of Menlo Park, N. J. 
Wm. Cabman, of Menlo Pork, N. J. 


THOMAS ALVA EDISON. (l.s.) 

































A.D. 1879, mb September. N° 3794. 


Apparatus Employed in Oonneotion with Telephones. 


LETTERS PATENT to Arnold White, of Queon Victoria Streol, in the City of 
London, for tho Invention of " Improvements in Apparatus Employed in 
Connection with Telephones for the Purpose of Notifying and of 
Facilitating and Obtaining Interchangeable Communication between 
Telephonic Circuits.” A communication from Thomas Alva Edison, ot 
Menlo Park, in tho State of Now Jersey, in tho United States of Amorico. 
Sealed tho 12th December 1879, and dated the 20th September 1879. 


PROVISIONAL SPECIFICATION loft by the said Arnold White at the Office 
of tho Commissioners of Patents on the 20th September 1879. 

Arnold White, of Queen Victoria Street, in the 
bents in Apparatus Employed in Connection with Telcthonhi fob^the 

5 Purpose of Notifying and of Facilitating and Obtaining iNTERCHUtaEABLE 

Communication between Telephonic Circuits. Acommunu£ g f 
Alva Edison, of Menlo Park, in tho State of Now Jersey, in tho United States ot 
America, 

This Invention relates to improvements in tbe mothodsby wUob two 
10 electric circuits may be quickly united to form one, and as quic ? . . electrical 
again constitute two distinct circuits. And further, m wpojvemenUaMn 'M 
annunciators whereby notice is conveyed to an attendant a combination 

other distant point that his attention is required. And further in the comninaiio 
, of an electrical circuit connecting hoard and an o octriea anmmcmtor 
15 especial purposes and usos of telephonic exchanges and other:staU mbs._ 

Ry means of this Invention tho Mowing advantages arQ °““ 1- tb offoring 
1st. Condensation of a large number of wires m a small space, thus oner g 
extraordinary facilities for rapid cross connections. 

• S£a^“SS3».«-*i..i^ “* 

. 4tk Thc'ffldhld wbToby til. numbar or name of tho 

a exposed to tho attendant as well also as tho superior simplicity and oQecuvone 


[Price CtZ.] 










2 A.D. 1879.—N° 8794. £sSsgf 


White'tt Improvements in Apparatus Employed in Connection with Telephones, 


In carrying out this Invoution the apparatus is constructed and arranged in tlio 
following’mannor:— 

A series of two or more olectro magnots aro affixod to a parallel bar supported 
within a frame; tliero may be one or moro rows of theso magnets one above tho 
other, or otherwise arranged. Attached to a cost metal frame which supports each { 
electro magnet is an anglo piece, which serves tho doublo purpose of providing a 
means for securing tbo whole to the faco of the parallel bar and of projecting a 
fixture, to which is attached the device for disclosing a number, name, or other sign 
indicative of tho particular magnet in action. This device consists of a small metal 
shutter, hinged at tho bottom, so that when in an upright position it conconls the 10 
sign character, but when released and permitted to fall it uncovors it. The sign 
may be either upon tho roverso faco of the drop itself or upon tho faco of a stationary 
support immediately behind it when it is in an upright position. The drop is held 
in an upright position by means of a niche or other device affixed to or upon tho 
end of an extension of tho armature of tho oloctro-magnot, and upon tho drop tho 15 
extension is pivotted near its junction with the nrmature in such a manner that 
when the armature is depressed by the attraction of tho magnet the oxtendod aria 
is raised and tlio drop is released from tho niche and allowed to fall. In order to 
reduce the friction between tho arm and tho drop to a minimum tho drop is brought 
os near as possible to an upright position without reaching a dead contre, from 20 
which it could not movo by its own gravitation. 

The circuit connecting board is supported within the same frame as the electro¬ 
magnets and immediately underneath them, and consists of a series of metal upright 
and horizontal bars so arranged that tho upright bars lie across tho face of tho 
horizontal bars without being in contact. This is effected by setting them into 25 
grooves cut in tho face of a wooden or other nonconducting frame, which grooves 
are deeper for the horizontal than for the upright bars. 

In order that tho surfaces of both may present ono common plane the horizontal 
bars are cast with projecting lugs of a height equal to tho thickness of the upright 
bins, and of n thickness n trifle less than tho space between tho upright bare. In 30 
this manner two series of bars, ono upright and ono horizontal, are laid across each 
other and made to present ono common plane without being in actual contact, 
Holes aro then drilled (for tho insertion of a metal pin) at every point of crossing 
of the two series of bars, the object being by the insertion of tho pin at will to 
obtain metallic connection between any two uprights. 35 

Tho function of the horizontal bare is simply to intorsect or join together by tho 
aid of tho pin any two of tho uprights. 

It is apparent that this relative position may bo changed and the uprights mado 
to Bervo os the connection for any two horizontals. 

The electrical operation of this tolephono combination of annunciator and inter- 40 
connecting bars will appear from the following description of the arrangement of 
tho circuit:— 

The conducting wire conveying the electro currents from the distant station is 
brought to a small screw cup attached to the top of the frame, and passes from 
thence by means of fino insulated wires directly to one end of the electro magnet of 45 
the annunciator, and from the other end to tho top of an upright bar, and traversing 
this intersects ono of tho horizontal bars by means of tho metal pin, this particular 
horizontal bar being connected by wire with the earth; thus tlio circuit is com¬ 
plete from the line to tho earth through tho annunciator magnot and upright bar, 
cadi electro magnot and upright bar serving for a separate lino. 5® 

If now it is desired to join electrically any two tolophono linos it is only necessary 
to removo the pins of each from tho point of junction with tho earth connected hori¬ 
zontal bar, and insort them at tho point of junction of their respective uprights ami . 
a free horizontal. 

. It will be soon that tho two lines which are thus mado ono electric circuit {5 
continue to pas3 thro’ thoir respective annunciators, and it is only necossary for 
either distant station to transmit an electric pulsation from thoir signal batteries or 


ESSS. A.D. 1879.—N° 8794. 3 

White's Improvements in Apparatus Employed in Connection with Telephones. 

machines to operate the annunciators, and thus signify that thoy have finished and 
wish their wires separated from each other and reconnected with tho oarth bar, the 
annunciator drops previously thrown down by the driginal signals having been 
meanwhilo restored to thoir upright position by the attendant. Tho circuits may 
5 be made in many ways through tho olectro magnots and bars, but the ono herein¬ 
before described iB found to bo convenient in practice. 

It is of coureo apparent that when A wishes to be put in communication with B 
be has but to signal to tbo attendant, who connecting his telephone in circuit 
inquires his wishes. Upon receiving the response ho immediately connects A and B, 
10 as before described j A then calls B direct, B responding affects the annunciators 

The cessation of all movement in tho armatures of the electro magnets is tho 
signal to the attendant that A and B nre now talking. He then restores tho drops 
to position and awaits thoir simultaneous dropping os his signal to separate 
15 them. 








4 A.D. 1879.—-N° 8794. 


White’s Improvements in Apparatus Employed in Connection with Telephones. 


SPECIFICATION in pursunneo of the conditions of the Lotters Patent filed by 
the said Arnold Whito in the Groat Seal Patent Offico on tho 19th March 
1880. 

Arnold White, of Queen Victoria Street, in the City of London. “ Improve¬ 
ments in Apparatus Employed in Connection with Telephones for the 5 
Purpose of Notifying and of Facilitating and Obtaining 'Interchangeable 
Communication between Telephonic Circuits.” A communication from abroad 
by Thomas Alva Edison, of Menlo Park, in the Stato of Now Jersey, in the United 
States of America. 

Tho said Invention relates to improvements in tho methods by which two Bcpamto 10 
electric circuits may bo quickly united to form ono, and as quickly divided so as to 
again constitute two distinct circuits. And further, to improvements in electric 
annunciators, whoroby notico is convoyed to an attendant at a control station or 
other distant point that his attention is required. And further, in the combination 
of an electric circuit connecting board, and an electric nnnuncintor for the especial 15 
purposes and uses of tclophonic exchanges and other stations. 

By means of the Bnid Invention tho following advantages nro obtained:— 

First. Condensation of a largo number of wires in a small space, thus offering 
extraordinary facilities for rapid cross connections. 

Second. Economical construction. SO 

Third. Enabling ono attendant to attond to a larger numbor of wires than by the 
methods heretofore in use. 

Fourth. The method whereby tho number or name of tho station requiring 
attention is exposed to the attendant, as well also ns tho superior simplicity and 
effectiveness of the apparatus, 25 

In carrying out the said Invention the apparatus is constructed and arranged in 
the following manner, referenco boing made to tho Shoot of Drawings hereunto 
annexed, in which Figure 1 represents a front elevation of tho apparatus, and 
Figuro 2 is a transverse vertical section of tho same. 

To a bar A supported within a frame B is affixed a series of two or moro electro 30 
magnets C, by means of cast metal framos D and screws. 

There may bo ono or moro rows of theso magnets one abovo tho othor, or otherwise 
arranged. Tho Drawing represents two rows of electro magnets C, carried respectively 
by two bars A, A, arranged one abovo the other, oacli row containing 12 electro 
magnets. Tho metal frames D which support the electro magnets form anglo pieces 35 
which serve tho double purpose of providing a means for securing tho electro 
magnets to tho face of tho bars A, and of carrying a device for disclosing n number, 
name, or othor sign indicative of the particular magnet in action. 

This device consists of a small metal drop or shutter a hinged at tho bottom 6,so 
that when in an upright position it conceals tho sign or character, but when 40 
rolensed and permitted to fall it uncovers it. Tho sign may bo either upon tho 
rovorse face of the drop itself or (as is assumed in tho example illustrated) upon the 
fnco of a stationary support 0 immediately behind tho drop a, or when it is in an 
upright position. Tho drop is hold in an upright position by means of a niche or 
other device affixed to or upon tho end of nn extension cZ of the arnmturo e of tho 45 
electro magnet, and upon tho drop tho extension d is pivotted at/, near its juncture 
with tho armature e in such a manner that when tho armaturo is depressed by tho 
attraction of the magnet, tho oxtonded arm d is raised, and tho drop is released 
from tho nicho and allowed to fall. In order to reduco tho friction between the 
arm d and the drop to a minimum, tho drop is brought as near as possible to an 50 
upright position without reaching a doad contre, from which it could not movo by 
its own gravitation. 


A.D. 1879.—N“ 3794. 


White's Improvements in Apj)aratus Employed in Connection with Telephones, 

In the Drawing, Figuro 1, tho drops of tho eighth and seventeenth electro 
magnots nro represented as down, exposing tho numbers 8 and 17 respectively, 
thoother drops being represented in tlioir raised position, concealing their respective 

5 ""The apparatus hereinbefore desoribed constitutes nn olcctric annunciator, which 
may bo used for conveying notice to an attendant at a central station or othor 
distant pnrt that liis attention is required. 

The circuit connecting board which formB another part of tho said Invention is 
supported within the same frame as tho electro magnets, and immediately under- 
10 neath them. It consists of a series of metal upright bars E, and of metal horizontal 
burs F bo arranged that tho upright bars lie accroas tho face of tho horizontal bars 
without being in contact with thorn ; this is effected by settling the horizontal bars 
upon tho faco of a wooden or othor non-conducting frame G, nnd supporting tho 
upright bars upon intervening bars H of wood or othor nonconducting material 
15 made of a suitable height. 1 1 1. 1? 

In order that tho surfaces of both tho upright burs E nnd the horizontal bars h 
may present ono common piano, tho upright bars are let into recesses in tho 
horizontal bars slightly exceeding in width tho width of the upright bars. In th 
manner two series of burs, one upright, and ono horizontal, are laid accross ouch other 
20 and made to present ono common plane without being in actual contact Holes 
are then drilled (for tho insertion of a metal pin I) at every point of crossing of the 
two series of bars, tho object boing by tho insertion of the pm at wiU tomtom 
metallic connection between any two uprights. Tho function of the homontal 
bars is simply to intersect or join together by the aid of the pin any two of tho 
25 uprights. It is apparent however that the converso of this arrangement may be 
adopted, that is to say, that the uprights may be made to servo as the connection 

f0r Th" y electrical^operation of this telephonic combination of annunciator and 
inter connecting bars or electric circuit connecting board will appear from tho 
30 following description of tho arrangement of tho circuits ,, ... 

upright bar, and traversing this intersects tho lowest 
» the metal pin, this particular horizontal bar being 

ns before mentioned. Tho circuit is thus complete from ho lino to the earth through 
tho nnnunicator magnet nnd upright bar. A similar a g pnet an( j upright 
case of all tho electro magnets and upright bars , seventh® 
bar serving for a separate line. One of *0 honzonU! bam Mg*®2 mit y to 
example assumed) is connected by a wire n with a P. . .. ay b e n y 0 to 
the apparatus in order that tho attendant attho cen^ • «>»» 

communicate with any ono of the twenty foui tolop telenhonio lines, it is 

“pp*t.tus. If now it U desi™l to ^ f^ifolrointo of junction with tho .trti,- 

through their respective annunciators. .. . , trio annunciator and electric 







6 A.D. 1879.—N° 8794. **** 

While's Improvements in Apparatus Employed in Connec tion with Telephones. 

B at nnotlior distant station, say, for example, one connected with No. 17 olectro 
magnet, 

A first signals to tho attendant at tho control station or oxcliango by sending an 
electric pulsation from its signal battery or machine to operate tho Ann.m. j ?|, r 
and the drop of No. 8 magnet falls displaying tho figure 8, ns shown in the Drawing' 5 
Figure 1. Tho attendant thou removes ono of tho pins from tho lowest horizontal’ 
bar, and places it in tho holo at the point of intersection of No. 7 horizontal bar 
with No. 8 upright bar, whereby No. 8 lino is placed in circuit with tho tnWho n e 
at tho exchange. Tho attendant noxt enquires of A his wishes, and receiving a 
response that ho wishes to be connected with No, 17 lino, tho attendant places 10 
the pm corresponding to No. 8 in tho holo at tho point of intersection of No. 8 
upright bar with ono of tho free horizontal bars, (tho second in tho cxnmplo 
assumed) and places tho pin corresponding to No. 17 in tho holo at the point of 
inter section of No. 17 upright bar with tho same horizontal bar. Lines Nos. 8 and 
17 aro then in circuit, and A calls B direct, B responding affects tho annunciator, 1J 
and the drop of No. 17 falls. Tho apparatus is then in tho condition indicated in 
the Drawing. Tho cessation of all movement in tho nrmaturcs of the electro 
magnets is the signnl to tho attendant that A and B aro now talking, he tbon 
restores the drops to their normal position and nwnits tlioir simultaneous dropping 
as his signal to separate the two linos by restoring tho two pins to their respective 20 
places on the lowest horizontal bar. 

It will bo understood that if roquired any other or all of tho lines may be 
similarly connected in pairs at tho same time. 

Wlipn a greater number of lines than that provided for in the cxamplo of apparatus 
iliustiatcd is required to bo connected with tho oxchange, an additional setof electro 23 
magnets may bo provided at tho side of those shown, and tho upright bars E may 
bo extended downwards ns represented at E', and an additional set of horizontal 
bars bo provided below tho others, as indicated at F 1 , in Figure 1. 

Having now described and particularly ascertained the nature of the said 
n/w t T° n ' “n * 10 mnn . ner m : vb . ich tho sa,n0 is or may bo used or carried into 30 
effect I would observe in conclusion that what I consider to bo novel and original 

“cnedTeUers ment is|- ““ t0 * th ° “ P ttrt 

, i T1 '°i e ° nera ! constructlon nn, i arrangement of electric circuit connecting 
board, whereby nny two separate electric circuits may bo quickly united to form 35 

tially ash^rcinbefor^^described" 8 ^ a8 “ in C ° nStitUta * W ° dMnCt circuil9 - subston - 
goneral construction and arrangement of olectric annunciator, 
substantmUy as and for the purpose hcremboforo described. 

unruly. Ihe combination of an electric circuit connecting board, and an electric 40 
arran S cd -bstantially in the manner and for the 

In witness whereof I, tho said Arnold White, have to this my Specification 
hundred and^eighty™*’ EIevcnth dn y of March - Ono thousand eighty 


ARNOLD WIHTE. (us.) 


LONDON: Printed liy Oxmian Eowi 
Printom tu thu Quoon’a 
Por Her Majesty' 








































A.D. 1879, 10th November. N° 4576. 


Electric Lamps. 


LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in the Stato of 
isow Jersey, United States of Amoricn, for tho, Invention of " Improvements 
in Electric Lamps, and in the Method of Manufacturing the same.” 
Sealed tho 6th February 1880, and dated the 10th November 1879. 


PROVISIONAL SPECIFICATION loft by the said Thomas Alva Edison at tho 
Oihco of the Commissioners of Patents on tho 10th November 1879. 

„M ,I 05 I f S AL Y A °P Menlo Park, in tho Stato of Now Jersey, United 

stales of America. » Improvements in Electric Lamps, and in the Method of 
0 Manufacturing the same.” 

It is necessary to practically subdivide tho electric light into a groat number of 
nnmnous points,[so that lamps connected in multiple may he employed without 
tee necessity of using conductors of great size for tho current to tho lamps. It is 
in o se .J“ 4,10 lamps should bo of great resistance. In tho Provisional 

specification of Patent dated Juno 17th, 1879, No. 2402,1 havo sot this forth, and 
o tamed lamps of groat resistance by employing long lengths of platinum or 
metallic wires pyroinsulated, and wound in such a manner that but small radiating 
sur ace is exposed to tho air, although a great length of wiro is used, 
u .. J1 y present Invention relates to lamps of a similar character, excopt that carbon 
im-eatis or strips aro used in place of metallic wires. I uso a block of glass, into 
“ ro . sc Alcd two platinum wires. Theso wires Bcrvo to convoy tho current to 
X 11, lnm P wit| iin a bulb, which is blown over tho lamp and united to tho 
fi ass block. The bulb is exhausted of air to about one millionth of on atmospboro. 
20 w f° n onds of these wires aro two clamps that socuro two other platinum 
U S | Iho burner consists of a filament or tliroad of carbon, proferably 
follow* 111 tl10 ° nd8 seouretl to 1,10 P latinum wirc9 ' tbo wlloIe boin S “ ntla 
Fibrous material, such as paper, thrend, wood, or any vogotablo or animal matter 
25 , . cnn bo carbonized, has tho ends secured to platinum wires, tho fibro is 

la such a shapo as to expose tbo least amount of snrfaco to radiation, such 
, a or spiral. Tho helix is secured to tho platinum wires by plastio 
li eat ’ fir tllQ wllole placed in a closed vessol free from air, and subjected to u 


icient to fully carbonize tbo fibre, and leave nothing but carbon. At tho 


[Price Gtl] 







Edison's Improvements in Electric Lamps. 

same time tlio effect of tho carbonization is to lock tho carbon to the platinum wiro 
and mnko good connection. 

These wires aro secured by the clamps to tlio two platinum wires in tlio bulb, 
and tho bulb is exhausted of air and sealod. Lamps of ono hundred ohms resistance 
may be mado in this manner, from which light from tlio incnndescont carbon is 5 
obtained. Tlio destruction of tho frngilo carbon by oxidation is provouted by tlio 
higli vacuum, which is obtained boforo sealing the glass bulb. 

Previously to my Invention enrbon sticks liavo been used, but llioy have only 
lmd a resistance of three or four ohms, uud none have been used in vacuum bulbs 
composed entirely of glass, except tho leading wires, lienco tho difficulties of 10 
sealing lending wires into glass, which would convey a current of sufficient strength 
to a lamp of but three or four olnns resistance is too grent to mnko such a lamp 
successful, but when the resistance of the lamp is 100 ohms or more the leading 
wires can bo very small, os they will then be a small factor in the total resistance 
of tho lamp, and will not heat so as to crack the glass. 15 

Lamp black, which has been placed in sealed crucibles, and subjected to a white 
heat for several hours, may bo kneaded with tar until it reaches such a consistency 
as to allow its being rolled out on flat plates to very thin wires, which are 
sufficiently flexible to allow of coiling into helices : after they arc rolled out to the 
proper length and size they aro coated with a iion-carbonizablo powder of liquid, 20 
and wound or coiled. 

The two ends are increased in size and secured to platinum wires, tho wliolo is 
then subjected to heat 111 a closed tubo, and tho volatilo constituents of the tar 
driven off and the balance carbonized, thus making a solid and homogeneous coil, 
which can be then united to the leading wires of the lamp, and a gloss bulb blown 25 
over it and exhausted of air, nnd tho lamp is then ready for uso. The non-carbonized 
material prevents the spirals from touching each other until the whole has so 
stilloned sufliciently to remain in its position. 

To assist in more rapidly manufacturing these spirals I somotimos wind tho 
flexible enrbon wires between metallic spirals, which after tho carbonization of tho 30 
tar are eaten away by acids, thus leaving tho carbon intact. I also sometimes roll 
a thread within tho compound of carbon and tar, so ns to allow of greater 
convenience in handling the same, and tho flexiblo carbon filamont is not so liablo 
to crack by its own weight in tho act of winding. 

, T° increase tho resistance of the lamp black tar compound I sometimes work it 35 
into a volatile powder, such as powdered camphor, oxide zinc, but to mako tho 
light insensitive to variations of the current a considerable mass of matter should 
be used, in order that the specific heat of tho lamp may bo increased, so that it 
takes a long time to reach its full brilliancy, and also to die away slowly. To do 
this it is better to have the carbon ns homogeneous ns possible, and obtain the 40 
requisite resistance by employing a filamont several inches long, and winding 
the same in a spiral form, so that the external radiating surface shall be small. 


Edison’8 Improvements in Electric Lamps. 


SPECIFICATION in pursuance of the conditions of tho Lotters Patent filed by 
tho said Thomns Alva Edison in tho Groat Seal Patent Office on tho 10th 
May 1880. 

Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United 
5 States of America. “ Imimiovemijnts in Ei.kcthio Lamps, and in the Method of 
Manufactuiiino the same." 

The object of this Invention is to produce electric lamps giving light by 
incandescence, which lamps shall liavo high resistance so as to allow of the 
practical subdivision of the electric light. 

10 Tlie Invention consists in a light giving body of enrbon wire, or sheets coiled or 
arranged in such a manner as to offer great resistance to the passage of tho eleetrio 
current, and at the same time present but a slight surfaco from which radiation 
can take place. 

The Invention further consists in placing such light giving body ot great 
15 resistance in a nearly perfect vacuum, to prevent oxidation and injury to tho 
conductor by tho atmosphere. . 

Tho current is conducted into tho vacuum bulb through platina wires sealed mto 

^Tho'lnvention further consists in tho method of manufacturing carbon conductors 
"0 of hhdi resistance, so as to be suitable for giving light by incandescence, and in the 
manner of securing perfect contact between tho metallic conductors or leading 
wires, and the carbon conductor. . . 

Heretofore Ii'dit bv incandescence has been obtained from rods ot carbon ot one 
to four ohms resistance placed in closed vessels, in which the atmospheric air has 
25 been replaced by gases that do not combine chemically with the carbon. I he 
vessel holding the burner has been composed of glass cemented to a metallic base. 
Tho connection between the leading wires and tho carbon lias been obtained by 
clamping tiie carbon to the metal. 

The leading wires liavo always been large, so that tlibir resistance shall bo many 
SO times less than the burner ; and in general the attempts of previous persons lias 
been to reducu the resistance of the carbon rod. Tho disadvantages ot following 
this practice are. that a lamp having but one to four olnns resistance cannot bo 
worked in great numbers in multiple arc without the oinp oyme.it of mam 
conductors of enormous dimensions, that owing to the low resistance of the lamp 
33 the leading wires must be of largo dimensions and good conductors, and a g ass 
globe cannot bo kept tight at the place where the wires pass in and are cemented 
hence the carbon is consumed because there must be almost a perfect vacuum to 
render the carbon stable, especially when such carbon is small m mass, nnd High in 
electrical resistance. , . , . , „ u , 

40 In the use of a gas in tho receiver at the atmospheric pressure, which, although 
not attacking tho carbon, servos to destroy it in tune by air was ling 
attrition produced by tho rapid passage of tho air over tho slightly coherent highly 
heated surface of tho enrbon. ,, . , _ „ fv, r „„ f i 

I have reversed this practico. I have discovered that evo , 

45 properly carbonized, and placed in a sealed glass bulb exhausted to one millionth of 
an atmosphere, offem from ono hundred to five hundred ohms 
passage of the current, and that it is absolutely stable at very high omperatuiM , 
that if the thread be coiled as a spiral, and carbonized, or if a"y fib ous vogetob^ 
substance which will loavo a carbon rosiduo after heating in a closod chambor be1 so 
0 coded, that as much os two thousand ohms resistance may be obta n d without 
presenting a radiating surfaco greater than three sixteenths o , 

such fibrous material bo with a plastic compound 

»ud tar, its resistance may bo mode high or low according to the amount of lamp- 






Edison’s Improvements in Electric Lumps. 


black placed upon it. I have also discovered that carbon filnmonts may bo made 
by a combination of tar and lamp-black, tho latter boing previously ignited in a 
closed cruoiblo for several hours, and nflorwards moistened and kneaded until it 
assumes the consistency of thick putty. Small pieces of this material may bo 
rolled out in the form of wiro ns small ns soven ono thousandths, 7/1000 of an e 
inch in dmmotor, and over a foot in length, and the snmo may be coated with a 6 
non-conducting iion-carbonizablo substanco, and wound on a bobbin, or ns a spiral 
and the tar carbonized in a closed chamber by subjecting it to high heat tho 
spiral after carbonization retaining its form. I sometimes roll a thread within tho 
compound of lamp-black and tar, so as to allow of greater convenience in handling in 
the same; and tho flexible carbon filnmcnt is not so liablo to crack by its own 
weight in tho act of winding. 1 

To increase tho resistance of tho compound of lamp black mid tar I sometimes 
work into it a volatile powder, such as powdered camphor, oxide zinc, but to mako 
tho light insensitive to variations of tho current a considerable moss of matter u 
should be used in order that tho specific beat of tho lamp may bo increased, so that 
it takes a long time to rench its full brilliancy and also to dio away slowly. 

To do this it IS better to liavo tho carbon as homogeneous as possiblo, and obtain 
the requisite resistance by employing a filament several inches long and winding 
tno same in a spiral form so that tho external radiating surliico shall bo small. All an 
these forms are fragile and cannot bo damped to the leading wires with suflicient 
iorco to ensure good contact and provent heating. I have discovered that if 
platinum wires are used and the plastic lamp-black and tar material bo molded 
around it that in tho act of carbonization there is an intimato union by combination 
and by pressure between the carbon ami platina, and nearly perfect contact is 05 
obtained without tho necessity of clamps, hence tho light giving body and tho " 
platina wires are connected and ready to be placed in the vnemim bulb. 

When fibrous material is used tho plastic lamp black and tar is employed to 
secure it to tho platina wires beforo carbonizing, lly using tho carbon wire of such 
high resistance lam enabled to use fine platinum wires for leading wires, as they 30 
will have a small resistance compared to tho light giving body, hence will not heat 
and crack tho sealed vacuum bulb. 1 

Platina can only be used, ns its expansion is nearly tho same ns that of glass. 

By using a considerable length of carbon wire and coiling it in such a manner that 
only a small portion of its entire surface radiates light, 1 can rniso tho specific heat 33 
of the whole and thus prevent tho rapid reception and disappearance of tho light, 
which on a plain wire is prejudicial as it shows tho least unsteadiness of the current 
by tho flickering of tho light, but if tho current is steady the defect does not show. 

I have carbonized and used cotton and linen thread, wood-splints, paper coiled in 
various ways also lamp-black, plumbago, and carbon in various forms mixed with 40 
tar and kneaded so that the sarno may be rolled out into wires of various lengths 
and diameters, each wiro however is to bo uniform in sizo throughout. If tho 
carbon thread i a |hnblo to bo distorted during carbonization it is to bo coiled 
between a helix of copper wire. Tho ends of tho carbon or filament aro secured to 
:r® P“\ tlna . , ndl "S w | res hy plastic carbonizable material and tho whole placed in 45 
lio carbonizing chamber. Tho copper which lius served to prevent distortion of 
the carbon thread is afterwnrds eaten away by nitric acid, and tho spiral soaked in 
water and then dried and placed in the gloss holder, and a glass bulb blown over 
10 ° k |u '" , g tube for exhaustion by a mercury pump. This tubo when 

ingn vacua 1ms been reached is hermetically sealed. 50 

' „, 1 . & ubstaiicos which _ aro not greatly distorted in carbonizing they may be 
fiifi ' a "° n - co " d » ofcln g non-carbonizing substance, which allows one coil or 
t Tn H,l 'ri 0nr - 0n t £ rc8 , t u > )0n nnd be supported by the othor. 
thr I ead h r I l™ Wln ^| Fl H'- 1 , sh< T ‘l 10 lam P sectionully. « is tho carbon spiral or 
oflamn wli tho thickened emls of tho spiral formed of tho plastic compound 5 a 
cervoT S aro the wires; h, h, aro tho clamps which 

servo to connect the platina wires comontod in tho carbon with tho leading 


A.D. 1879.—N° 4576. 5 

_ Edison!s Improvements in Electric Lamps. 

wiros x, sealed in tho gloss vacuum bulb; 0, c, are copper wires connected just 
outside tho bulb to tho wires as, as; m is tho tube, shown by dotted lines leading to 
tho vacuum pump, wliioli tubo is hermetically soaled near tho glass bulb after “tho 
bulb has boon exhausted of air, as aforesaid. 

5 Fig. 2 represents tho plustic material beforo boing wound into a spiral. 

Fig. 3 show the spiral after carbonization ready to have a bulb blown ovor it. 

I claim as my Invontion,— 

First. An electric lamp for giving light by incandosconco consisting of a filament 
of carbon of high resistance, made as described and secured to metallic wires, as 
]0 set forth. 

Second. The combination of a carbon filament within a receiver made entirely of 
glass, through which tho leading wiros pass and from which receiver the air is 
exhausted, for tho purposes sot forth. 

Third. A coiled carbon filament or strip arranged in such a manner that only a 
15 portion of tho surface of such carbon conductor shall radinto light, as set forth. 
Fourth. Tho method herein described of securing tho platina contact wires to tho 
carbon filament aud carbonizing of tho whole in a closed chamber, substantially a3 
set forth. 

In witnoss whereof, I, tho snid Thomas Alva Edison, have hereunto set my 
20 hand and seal, this 20 day of April, A.D. 1880. 

THOMAS ALVA EDISON. (l.s.) 

Witnesses, 

Cha». H. Smith, 140, Nassau St., N.Y. 

Guo. T. Pincknev, „ „ „ 



















A.D. 1879, 15 th December. N° 5127. 


LETTERS PATENT to Thomas Alva Edison, of Menlo Parle, in the State of Now 
Jersey, United States of America, for tlio Invention of Improvements in 
Electric Lamps and in the Method of Manufacturing the same. 

Sealed the 20tli February 1880, nnd dated the 15th December 1879. 


PROVISIONAL SPECIFICATION loft by the said at th ® 

Office of the Commissioners of Patents on the 15th Dec * | 

Thomas Alva Edison, of Menlo Park, in the State °J ^ W TU g rS ^.’ TH0 D of 
States of America. “ Improvements in Electric Lamps and in the Method 
5 Manufacturing the same.” . , _ . 

In a former application made by me for Letters Patent mGroat B^tau^n 
improvement in electric lamps is sot forth, wherein a ai d h o u .(j on 

in a glass bulb and the atmosphere removed as nearly as posable, 
is brought to incandescence by nri electric ( p rooess ' of manufacturing 
10 Aly present Invention relates to an lmpiovcincno u i , . 

the carbon filament and the means for securing the Bum nossiblo from foreign 
I make use of paper of the desired thickness, ui Hw■ » P” ,board 
substances or adulterations, and for this purpose I p narrow a trip of this 

, With suitable instruments, such as a punch andf.Iotouta nanows«p 
15 paper, preferably in the form of an elliptical bow or an arc ot a circle, 

the strip boing by preference wider than the other port • , ,, f mou jj 

A number of IL .pieces 1 form of 

preferably of wrought iron, and thoie is luicl on mom fa , ° (1 -, orte( ] p> v the 
a fiat piece of gas retort carbon or other dovmie that £ iooo of & S9U0 

20 heat. If several of theso are laid one on the othe . g us0 1 (1 to closo t h 6 

paper is interposed between each one and tlio next. , f about six 

mould, and the mould is raised veiy gradually to of 

hundred degrees Fahrenheit. This allows the volatile portmns of the paper to p 
away, and at the same time the mould retains the paparinits propel shapomia 
25 tho paper is preveuted from curling up or becoming di dianensed with 
likely to do if the heat was applied suddenly or the >g h Vr3 t Va E Ja a^ 
The mould is now placed in a furnace and heated almost to a white heat, antt 
then removed and allowed to cool gradually. 

[Price 6d.] , . . 










_ Edis on's Improvements in Electric Lamps, <tc. 

Tho carbon filaments will bo found to bo smnllor than tho cardboard blanks, and 
to be sufficiently strong and flexible for handling. Tho onds of tho carbon arc to 
be secured to tho metallic conductors in any convenient manner. 

The carbon filaments prepared ns aforesaid are very uniform in their resistance 
to the electric current, and I make them thin and of a sufficient length to offer a 5 
great resistance to tho passago of tho current. The clamps that connect the con¬ 
ductors to the ends do not require to be pressed with much force on tho carbon, 
became tl,o resistance to the passage of tho current between the clamp and tho 
carbon will be less than tho resistance of the carbon filament, henco but little heat 
will be developed at the clamps. In ordinary electric lamps the largo carbons do 10 
not ofler much resistance to the electric current, and unless tho damps nro very 
firmly pressed upon the carbon the current meets with considerable resistance at 
the clamps, and lienee heat is developed nt such clamps. 

The clamps that I prefer are made of a steel spring tipped at the ends with 
platina or similar metal. Tho spring is bent into a circlo or bow, and tho ends 15 
crossed and turned back towards eucli other, similar in shape to the figure 8, with 
the opening for the carbon between the spring ends at tho upper part; the object 
of this shape is that tho pressure of the chimps on the carbon may bo increased by' 
the expansion of the spring by the heat of the lamp instead of being lossened, as it 
would bo if the wire was only bent into a single bow. 20 

The spring clamps aro connected to the platina or similar conducting wires by 
clips, and the platina wires pass through tho glass of tho globe or bulb that contains 
t lo lamp; the air is to be exhausted from tho bulb by nny suitablo means, nnd it is 
prelorable to exhaust said air as perfectly as possible, say to the one eight hundred 
thousandth ol an atmosphere. 25 

The lamps aro suspended or supported in ally convenient manner and the electric 
current from a magneto electric machine or other source of electricity is passed 
tlnougli the lamp and brings tho carbon filament to a high incandescence, and the 
lamp is very durable, and a largo number of such lamps can bo placed in the electric 
circuit in multiple arc or otherwise, ns desired. 30 


A.D. 1870.—N° 5127. 

Edison’s Improvements in Electric Lamps, Ac. 


SPECIFICATION in pursunneo of tho conditions of tho Letters Patent filed by 
tho said Thomas Alva Edison iu tho Great Seal Patent Offico on the 15th 
Juno 1880. 

Thomas Ai.va Edison, of Menlo Park, in tho State of Now Jersey, United 
5 States of America “ Improvements is Electric Lamps and in ran Method of 
Manufacturing tiie same." 

In British Letters Patent, No. doFfi granted to mo November 10, 1879, an 
improvement in electric lamps is set forth wherein a filament of carbon is inclosed 
in a glass bulb nnd tho atmosphere removed ns nearly as possible, and tho carbon 
10 is brought to incnndcsccnco by an electric current to form the lamp. My present 
Invention relates to an improvement in the process of manufacturing tho carhon 
filament, and in tho means for securing the same to the conductors. I make uso of 
paper of tho desired thickness, ns free as possible from foreign substances or 
adulterations, nnd for this purpose I prefer and uso “bristol board.” With suitablo 
15 instruments, such as a punch nnd dio, I cut out a narrow strip of this paper, 
preferably in the form of an elliptical bow or an arc of a circle, tho ends of tho strip 
being by preference wider than the other portions. A number of these pieces ot 
paper are Inid flatwise in the bottom of a mold, preferably of wrought iron, and 
there is laid on them a light weight in the form of a flat piece of gas retort carbon 
50 or other device that will not be distorted by tho heat. If several of these aro laid 
one on tho other in the mold a piece of tissue paper is interposed between each ono 
and the next. A cover is used to close the mold, and the mold is raised very 
gradually to a temperature of about six hundred degrees Falir. This allows tho 
volatile portions of the paper to pass away, and at. the same time tho mold retains 
25 the paper in its proper shape and the paper is prevented from curling up or 
becoming distorted, as it would be likely to do if tho heat was applied suddenly or 
the light weight dispensed with. The mold is now placed in a furnace nnd hented 
almost to n white heat, and then removed and allowed to cool gradually. Tho carbon 
filaments will be found to be smaller than the cardboard blanks, nnd to bo 
30 sufficiently strong nnd flexiblo for handling. The ends of the carbon are to bo 


secured to the metallic conductors in any convenient manner. Tho carbon filaments 
prepared ns aforesaid nro very uniform in thoir resistance to the electric current, 
and I make them thin nnd of a sufficient length to offer n great resistance to the 
passage of tho current. Tho clamps that connect the conductors to the ends do not 
require to bo pressed with much force on the carbon, because the resistance to the 
passago of tho current between tho clamps and tho carbon will be less than the 
resistance of tho carbon filament, hence but little heat will bo developed nt 
the clamps. In ordinary electric lamps tho largo carbons do not offer much 
resistance to the electric current, and unless the clamps are very firmly pressed 
™ upon the carbon tho current meets with considerable resistance at tho clamps and 
hence bent is developed at such clamps. Tho clamps that I prefer are made of n 
steel spring tipped at the onds with platina or similar metal; the spring is bent 
into a circle or bow and tho ends crossed and turned back towards each other, 
.. “inilur in shape to tho figure 8, with the opening for tho carbon between the spring 
c " (l » at the upper part; the object of this shape is that tho pressure ot tho clamps 
on the carbon may be increased by the expansion of the spring by the heat of tho 
l ! l,,1 P instead of being lessened, as it would be if tho wire was only bent into a 
“ing'lo bow. The sprfng clamps are connected to tho platina or similar conducting 
wires by clips, and the platina wires pass through the glass of tho globe or bulb 
“ tlmt contains tho lamp ; tho air is to bo exhausted from tho bulb by any suitablo 
"loans, and it is preferable to exhaust said air as perfectly as possiblo, say to tho 
ol »o eight hundred thousandth of an atmosphere. The lamps are suspended or 
supported in nny convenient manner and tho electric current from a magneto 











4 A.D. 1879.—N° 5127. *«m. 

_ _ Htlhon’s Improvements in Electric Lam jv), <ic. 

oloctrio mnohino or other source of electricity is passed through tho lamp and brings 
tho carbon filament to a high incandescence, and tho lamp is vory durable, and a 
largo number of such lamps can be placed in the electric circuit in multiple' arc or 
otherwise, as desired. 

In tho Drawing,— j 

Fig. 1 is a vertical section of tho lamp complete. 

„ 2 is a side view in larger size of the clamping device. 

„ 3 is a section at tho lino so, x, in still larger size. 

„ 4 is the wire forming ono of tho clamps before it is bent up to shape. 

» 5 is tho papor blank beforo it is carbonized, and 10 

„ G is a section of tho box. 

The blank a is cut out of papor material, such ns " bristol-bonrd,” in tho proper 
shape, tho form shown in Fig 5 is preferred; tho same is lnid in the metal mold 6 
and when several are laid ono on tho other pieces of thin papor nro introduced 
between. Tho weight d is laid on these, it is to bo heavy enough to prevent the 15 
paper curling up under tho action of the heat, but it allows the paper to contract 
as the volatile matters are expelled by the heat. This weight d is of gas retort 
carbon. Tho cover e is placed on the mold and secured, and tho mold is heated as 
before described. 

The carbon filament i forms tho lamp when rendered incandescent by tho electric 20 
current passed through it. The clamp is mado of tho wire h, at tho ends of which 
are tips or small rivets r of platina or similar material. The wiro is bent up and 
crossed, as shown, so as to act as a spring in clamping the end of the carbon 
filament that is placed within such clamp. The wire is attached to a small stock o, 
into which tho conducting wire t passes and is clamped. 25 

Tho conductors for the two ends of tho carbon arc inserted into the glass and the 
latter intimately melted around them, the carbon and damps are connected to the 
wires and tho parts introduced within tho neck of the bulb to and the "lass melted 
at v; the air is exhausted from the globe by tho tube k that passes away, as shown 
by dotted lines, and the tube melted together while tho vacuum is maintained. 30 
the lamp is ready for the conductors to be attached to it, nnd the carbon is 
rendered incandescent by the current that passes through the samo. It is durable 
““ere is nothing to combine with the carbon, and it is substantially 
indestructible. 

I claim as my Invention,— 35 

First. An electric lamp formed of carbonized papor. 

Second. The method herein specified of manufacturing carbons for cleetric lights, 
consisting in exposing the filament of paper to tho action of heat in a mold to drivo 
olt tlm volatile portions and carbonizo the paper, substantially as sot forth. 

.third. A carbon for electric lights made ns a filament with the ends broader for 40 
the clamping dovices that councct the conductors. 

1 Fourth. The clamp for the carbon of an electric lamp composod of a bow or 
elliptical spring with the ends crossing each other and receiving between them the 
carbon, substantially ns set forth. 

In witness whereof, I, tho said Thomas Alva Edison, liavo hereunto set my 45 
hand and seal, this Eighteenth day of May, A.D. 1880. 


Witnesses, 

Stockton L. Griffin, 
John F. Randolph. 


THOMAS ALVA EDISON, (i.s.) 












A.D. 1879, 31st December. N° 5335. 


LETTERS PATENT to Arnold White, of Queen Victoria Street, in tho City of 
London, for tho Invention of " Improvements in Telephones.” A com¬ 
munication from abroad by Thomas Alva Edison, of Menlo Park, in the State 
of Now Jersey, in the United States of Amorica. 

Sealed the 10th March 1880, and dated tho 31st December 1879. 


Arnold White, of Queen Victoria Strcot, in the City of London. “Improve¬ 
ments in Telephones.” A communication from abroad by Thomas Alva Edison, 
o of Menlo Park, in tho State of Now Jersey, in tho United States of America. 

This Invention relates to improvements in and connected with the receiving 
apparatus of telephones, in respect of which Lottcrs Patent were granted to the 
said Thomas Alva Edison, dated respectively the 30th July 1877, No. 2909, and the 
15th June 1878, No. 239G. 

10 According to the first of tho said former Letters Patent tho receiving apparatus 
was provided with a frictional surfneo moved by power, and acting in connection 
with tho electric current to vibrate a tympan and produco tones corresponding to 
thoso actuating the transmitting apparatus. According to the second of the said 
former Letters Patent tho said frictional surface was composed of chalk combined 
5 with a chemical substance and kept moistenod with water. 

Now according to tho present Invention it is proposed to dispense with the 
chemical substance previously employed in combination with tho chalk, and to use 
the latter alone moistenod with distilled or puro water. 

In carrying out tho said former Invention it has bcon customary to use a metal 
20 6 P™3 or arm tipped or faced with platinum in contact with tho chalk body of the 
receiving apparatus. Now, according to tho present Invention, it is proposed to 
employ a metal spring or arm tipped or faced with paladium, whoroby tho degree 
of frictional variation is increased under tho action of a given strength of electric 
cun-out, and a corresponding augmentation in tho volume of sound is obtained. 

0 Another part of the present Invention relates to tho arrangement of the con- 
hections of the induction coil in which the several parts of the apparatus are placed. 


























Specification. 


White’s Improvements in Telephones. 


In carrying out this part of tho Invention it is found advantageous to pluco the 
receiving apparatus in a tertiary circuit in liou of in tho secondary circuit; but it is 
found that by reason of the presence of two continuous circuits, vie 1 ., tho primary 
and tertiary circuits, the full effect of tho current from tho distant station is not 
obtnined upon the receiving apparatus, a portion of it pnssing from the secondary to j 
the primary circuit. In order to obviate this dofect, a key is placed in tho primary 
circuit, so arranged as to keep that circuit open while tho current from tho distant 
station is acting upon the receiving apparatus, the said key being depressed for the 
purpose of closing tho primary circuit when it is desired to actuate tho transmitting 
apparatus. It has beon found,- however, that upon opening or closing this key a 10 
powerful inductive discharge is directed upon tho receiving apparatus at tho sumo 
station, which discharge has a deteriorating effect upon tho surfaco of the chalk 
body of tho receiving apparatus. 

- According to this part of the present Invention tho defect before mentioned is 
obviated by opening tho tertiary circuit prior to tho closing of tho primary circuit, 15 
and closing tho tertiary circuit to leave it in condition to bo acted upon by a 
current from tho distant station, immediately after tho closing of tho primary 
circuit, and also by opening the tertiary circuit prior to tho opening of tho primary 
circuit, and closing the tertiary circuit immediately thereafter. 

In carrying tliin part of tho present Invention into effect, these conditions are 20 
fulfilled by tho employment of a singlo key arranged in the following manner, 
vis 1 .:—Ono of tho wires from tho tertiary coil, and ono of tho wires from the primary 
coil, are permanently attached to tho lever of the key, and tho othor wire of tho 
tertiary coil is bifurcated, and tho ends of its two lengths aro provided with contact 
points placed ono at each sido of tho lever of tho koy, but at such a distance 25 
therefrom as to admit of a third contact point connected with the other wire of tho 
primary coil being brought into contact with tho lover of tho key while it is 
passing from ono to tho other of the two contact points of the bifurcated tertiary 


SPECIFICATION in pursuance of tho conditions of tho Letters Patent filed by 30 
I880 Baid Arn ° ld Wlllite ‘ n th ° GrCat Seal Pat ° nt 0ffic ° °“ the 141,1 April 
Arnold White, of Queen Victoria Street, in the City of London. “ Improve- 
ments in Telephones." A communication from abroad by Thomas Alva Edison, 
of Menlo Park, in the State of Now Jorsoy, in tho United States of America. 

The said Invention relates to improvements in and connected with tho receiving 
apparatus of telephones, in respect of which Lottora Patent woro granted to tho 
Bald 1 homos Alva Edison, dated respectively the Thirtieth July One thousand eight 
hundred and seventy seven, No. 2909, and tho Fifteenth Juno Ono thousand eight 
hundred and seventy eight, No. 2390. 40 


White's Improvements in Telephones. 


According to tho first of tho said former Lottors Patent the receiving apparatus 
was provided with a frictional surface moved by power and acting in connection 
with tho electric current to vibrato a tympan, and produce tonos corresponding to 
those actuating tho transmitting npparntu.fi. According to the second of the said 
5 former Letters Patent the said frictional surfaco was composed of chalk combined 
with a chemical substance, and kept moistened with water. 

Now, according to tho present Invention, it is proposed to disponso with tho 
chemical substanco previously employed in combination with the chalk, and to uso 
tho latter nlono moistened with distilled or pure water. 

10 In carrying out tho said former Invention it has been customary to use a metal 
spring or arm tipped or faced with platinum in contact with tho chalk body of the 
receiving apparatus. Now, according to tho present Invention, it is proposed to 
employ a motal spring or arm tipped or faced with paladium, whereby the degree 
of frictional variation is increased under tho action of a given strength of electric 
15 current, and a corresponding augmentation in tho volume of sound is obtained. 

Another part of the present Invention relates to tho arrangement of tho con¬ 
nections of tho induction coil in which tho several parts of tho apparatus are 
placed. 

In carrying out this part of the Invention it is found advantageous to place tho 
20 receiving apparatus in a tertiary circuit in liou of in the secondary circuit j but it 
is found that by reason of tho presence of two continuous circuits, vis., the 
primary and tertiary circuits, the full effect of the current from tho distant station 
is not obtained upon tho receiving apparatus, a portion of it passing from the 
secondary to tho primary circuit. In ordor to obviate this defect a koy is placed in 
25 the primary circuit, so arranged ns to keep that circuit open while the current from 
tho distant station iB acting upon tho receiving apparatus,, tho said key boing 
depressed for tho purpose of closing the primary circuit when it is desired to actuate 
tho transmitting apparatus. It 1ms been found, however, that upon opening or 
closing this koy a powerful inductive disclmrgo is directed upon tho receiving 
30 apparatus at tho samo station, which discharge has a deteriorating effect upon the 
Burfnce of the chalk body of tho receiving apparatus. ' 

According to this part of tho present Invention tho dofect before mentioned is 
obviated by opening tho tertiary circuit prior to the closing of the primary circuit, 
and closing tho tertimy circuit to leave it in condition to beaded upon by a current 
35 from the distant station immediately after tho closing of tho primary circuit, and 
also by opening the tertiary circuit prior to tho opening of tho primary circuit, and 
closing the tertiary circuit immediately thereafter. 

In carrying this part of the presont Invention into effect theso conditions are 
fulfilled by tho employment of a Bingle koy arranged m the following manner, 
40 videlicet Ono of tho wires from tho tertiary coil and ono of the wires from the 
primary coil are permanently attached to the lover of the key, and the other wire 
of tho tertiary coil is bifurcated, and the ends of its two lengths aro provided with 
contact points placed one at each side of the lever of the key but at such a 
distance therefrom as to admit of a third contact point, connected with the other 
45 wire of tho primary coil, being brought into contact with the Jovcr of ho key 
while it is passing from ono to tho other of the two contact points of tho bifurcated 

LnMdT^that tho Baid Invention may be porfcclly understood, I shall1 describe> a 
complete set of instruments for the purposes of telephonic communication with t o 
30 Invention applied thereto, and in so doing shall rofor to the several ligmes on the 
accompanying Sheet of Drawings, tho same lottors of reference in which indicate 
corresponding parts in all tho Figures. . , , ,. 

Figure 1 of tho accompanying Drawings represents m sectional elovat on a 
general viow of tho instruments and their connections for the purposo of toloplion o 
60 communication between two stations, marked respectively No. 1 t o 

transmitters being drawn to their natural sizo, whilst tho otlici parts ol tho 
apparatus aro drawn to a scale of one half size. 






4 


A.D. 1879.—N° G335. 


A.D. 1879.—N° 5335. 


White's Improvements in Telephones. 

Figuro 2 represent3 an elevation of ono of the receivers, shown detached with tho 
cover removed, and Figuro 3 is a trnnsvorso section of tho samo. 

A, A, are tho transmitters; B, B, aro tho receivers; C, 0, uro tho batteries; D, D, 
arc tho induction coils, a being their primary circuit (shown in thick lines) in which 
the transmitter is placed; h, their secondary circuit (indicated in thick dotted lines), 5 
which constitutes tho main lino, and c, thoir tortiary circuit (donoted by Berios 
of short thick lines and dots) in which tho receiver iB placed; E, E, aro relays, and 
F, F, are call bolls or soundors, d, d, being local circuits (indicated by a sories 
of short fino lines in tho Drawing), in which tho call boll or sounders aro placed. 

Tho transmitter is constructed in tho following mannor:— 10 

e is a shell of metal (by prcforenco cast iron), on which is secured a disc / of 
brass (for example) platinized on its top surface /', around which disc is arranged a 
ring g of vulcanite or other suitablo non conducting material projecting abovo tho 
surface of the disc for a sufficient height to form a cup. Into this eup is inserted a 
button h of carbon (by preference tho finest lamp black, moulded and consolidated 15 
• under pressure), and upon tho top of this button is placed another metal disc e\ 
platinized upon its surfaco i 1 . Tho terminal a 1 of tho divided portion a‘ of tho 
wire a is connected to tho disc i by means of a strip k of platinum, whilst tho 
terminal a 2 of such portion of the said wiro is attached to tho shell e. The carbon 
button h, with the metal disc i, is thus intorposod in tho electric circuit, and it is so 20 
arranged as to be susceptible of mechanical influence from tho exterior in tho 
following manner:— 

On tho rim of the shell e is placed a membrane or tympan l of mica or iron (for 
exomplo), which is held firmly at its edges by tho mouth piece to, attached by screws 
to the shell e, the tympan being thus clamped between tho mouth piece and the 25 
shell. The tympan is provided with a boss at its centre, through which passes a 
screw n, tho point of which bears upon the disc i faced with nonconducting 
material. In fitting the parts together, the screw n is turned until tho tympan f, 
tho disc i, and the carbon button h aro brought into such relationship ns to produce 
a minimum, but actual contact between tho surfaces of all, but not to establish tho 30 
contact to such an extent as to constitute an initial degree of pressure. 

The apparatus operates in tho following manner:— 

By producing sound (say for example, speaking) into tho mouth pieco to, tho 
tympan l is thrown into vibration, and the effect being transmitted to tho disc i, 
and the carbon button h, their positions in relation to each othor aro varied, greater 35 
or less intimacy of contact being produced between tho two surfaces of the carbon 
button li and tho discs i, f, on opposite sides of it. By these moans a greator or less 
number of points in tho contiguous surfaces are brought into contact as tho tympan 
is vibrated, whereby the resistance to the passage of the current is varied, and tho 
current passing through the primary circuit a is transformed into an undulatory 40 
one; tho induced current passing through tho secondary circuit or main lino h is 
also converted into an undulatory current, and thence a similar change takes placo 
in tho induced current passing through tho tortiary circuit c, in which tho rcceivor 
at tho distant station is placed, tho undulations of which current exactly correspond 
to tho waves of sound which originally actuated tho tympan at tho sending 45 
station. 

Tho reeoivers B, B, aro constructed in the following manner, reforonco boing had 
to tho genoral view, Figure 1, and tho details, Figures 2 and 3:— 

o is a cylinder of chalk, moulded upon a shaft p, which is supported in bearings 
q, q, attached to tho casing r, and is extended boyoud tho casing, and provided at 50 
its outer extremity with a worm wheel s, with which engages a worm s* on a 
spindle /, the latter being provided with a crank linndlo t' for tho facility of turning 
tho worm s', and thonce imparting rotary motion to tho chalk cylinder, n is a disc 
or tympan of mica, which is attached at its edges by tho cover v, and scrows to tho 
casing r and carries at its centre a strip or arm u l of brass faced or tipped with o5 
paladium at v", which projects over tho cylinder o, and is maintained in yielding 
contact with tho chalk by means of an india rubber spring or cushion w, the prossuro 


White's Improvements in Telephones. 


of which is rogulatod by means of a scrow w\ Tho terminal 6 1 of tho dividod 
portion c 3 of tho tortiary wiro o is connected with the brass strip or arm v\ and tho 
terminal c ! of such portion of tho said wiro is connected to one of the bearings q, q, 
of tho shaft p on which tho chalk cylinder o is mounted, tho clmlk cylinder o and 
5 the brass strip or arm id are thus in tho circuit, bo that the electric ourront is caused 
to puss from tho brass strip or arm to nnd through the clmlk cylinder at the point 
of contact with tho strip or arm. Tho chalk is moistonod with pure or distilled 
water at long intervals, so as to maintain it in a humid condition, nnd when the 
eleeiric current passes, a chemical action is produced on tho surfaco of the cylinder, 
10 nnd among other parts at the point of contact of the strip or arm therewith. 

Tho receipt of an oral communication takes place under tho following conditions, 


vUlelieit :—Tho crank handle t l is turned by hand in either direction at pleasuro 
so as to impart rotary motion to tho chalk cylinder whereby the disc or tympan u 
is drawn forwards or thrust backwards according to tho direction in which the 
15 cylinder is rotated, when now an undulatory current the result of tho actuation 
of tho tympan at tho sending station, as hereinbefore described, traverses tho 
tertiary circuit, a variable degree of lubricity in accordance with tho undulations 
of the current is produced on tho surface of the chalk, and tho metal strip or arm 
is proportionately released, allowing tho tympan to return towards its normal 
20 position. This action being continued so long as tho cylinder is rotated and tho 
current is passing, the tympan u is caused to vibrate in unison with the tympan of 
the transmitter at tho sending station nnd audible sounds aro produced at x corre¬ 
sponding to tho vocal sounds which originally actuated the tympan of tho transmitter 
at the sending station. 

25 Tho several connections aro clearly indicated in the Drawing, tho presonco of a 
curve at tho point of intersection of two lines denoting that the wires represented 
pass one behind the other and aro not connected with each other. 

In using tho apparatus the tertiary circuit is opened prior to the closing of the 
primary circuit, and is closed to leave in condition to bo acted upon by a current 
30 from tho distant station immediately after tho closing of the primary circuit, and 
tho tertiary circuit is opened prior to tho opening of tho primary circuit and closed 
immediately thereafter. These conditions aro fulfilled by the - employment of a 
single key G arranged in tho manner shewn in Figure 1 of tho Drawings and next 
hereinafter described. 

35 The wire c 3 of the tertiary circuit c and tho wire a 3 of the primary circuit a are 
permanently attached to the lever y of tho key G, and the othor wiro (c‘) of the 
tertiary circuit is bifurcated, as shown at c 6 , c°, and the ends of these two lengths 
c 5 , c", aro provided with contact points 3, 4, placed one at each side of the lever y 
of tho koy G, but at such a distance therefrom as to admit of a third contact 
point 5 connected with tho other wiro (a 4 ) of the primary circuit a being brought 
into contact with the lever of the key while it is passing from one to the other of 
the two contact points of the bifurcated tortiary wire. During the normal con¬ 
dition of tho apparatus tho keys G are in the positions indicated in the Drawing, the 
primary circuit boing opon and the tertiary circuit boing closed. When now. it is 
15 required to send a communication from either station, tho key G of that station is 
depressed so as to cauao it to leave the contact point 3 of tho bifurcated wiro c of 
tlio tertiary circuit c, and bring it into contact with the contact point 4 of the said 
"'ire, By this movement tho tortiary oircuit is first opened, then tho key being 
„ brought into contact with tho contact point 5 tho primary circuit is closed, and 
5U finally when tho lover of tho koy arrives at tho contact point 4 the tertiary circuit 
is closed in readiness to bo acted upon by a current from the distant station. 
When tho key is released in order to opon the primary circuit tho lover of tho key 
first leaves the contact point 4, thus opening tho tertiary circuit, then loaves the 
“ntnet point 5, thus oponing tho primary circuit, and finally arrives at the point 3, 
3 thereby closing tho tertiary circuit nnd placing it in a condition to bo acted upon 
“y a current from tho distant station. _ . 

Before sending an oral communication tho call bell or sounder F at tho distan 



A.D. 1879.—N° 61 


White's Improvements in Telephones. 


station is actuated so as to notify that a communication is about to bo sent. This 
result is obtainod by the act of depressing the key H at tho sending station, thus 
completing the secondary circuit whilst isolating the apparatus at the sending 
station, and exciting tho relay E at tho distant station ; by the action of this relay 
the local circuit d is completed nnd the bell F is sounded, a notification being thus 5 
afforded that a communication is about to be sent. Tho koy H iB then released 
and the key G is operated, and the sender speaks into the mouth pieco m of the 
transmitter A, and the speech is heard at tho receiver B of tho distant station, os 
hercinboforo explained. 

Having now described and particularly ascertained tho nature of tho said 10 
Invention and tho mannor in which tho same is or may bo used or carried into 
effect, I would obsorvo in conclusion that although I have described various dovicos 
and arrangements which aro necessary or desirable in carrying out the said 
Invention, yet I make no claim to any of tho said devices or arrangements as 
forming any part of tho present Invention, except as hereinafter mentioned, but 15 
what I consider to bo novel and original, nnd therefore claim as tho Invention 
secured to me by tho hereinbefore in part recited Letters Patent is,— 

First. Constructing tho frictional Burfnce of tho rotary body of tho recoivor 
of clmlk moistened with pure or distilled water, substantially as hereinbefore 
described. 20 

Secondly. In a receiver constructed as herein set forth the employment in 
contact with the surface of tho moving chalk body of a metal strip or arm tipped 
or faced with paladium, substantially as hereinbefore described. 

Thirdly. The mode of controlling the opening and closing of the primary nnd 
tertiary circuits by tho uso of a singlo key, so arranged that tho tertiary circuit 25 
shall bo opened before tho primary circuit is doted or opened, and shall bo closed 
immediately afterwards, substantially as and for tho purpose hereinbefore described. 

In witness whereof, I, tho said Arnold White liavo to this my Specification 
set my hand and seal, this Twelfth day of April, One thousand eight 
hundred and eighty. 30 


Witness, 

W. B. Hercek, 

Clerk, 

11, Queen Victoria Street, 
E.C. 


ARNOLD WHITE. (L.s.) 


LON] . 


Printed by Gi 
































A.D. 1880, 3rd jA.YVAitr. N° 33. 


Developing Electric Currents for Electric Lights. 


LETT HRS PATENT lo Thomas Alva Edison, of -Menlo Park, in the Stulo of 
New Jersey, United States of America, for an invention of " IMPROVEMENTS 
in Apparatus Koit Dkvki.opino Electric CURRENTS and Regulati-no tiib 
Action ok the same in Circuits that pass to Electric Lights or 
Electro Magnetic Engines." 


PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at the 
Office of the Commissioners of Patents on tlio 3rd January 1880. 

Thomas Alva Edison, of Menlo Park, in the Stnto.of Now Jersey, United S tates 
of America. “ Improvements in Apparatus for Developing Electric Currents 
5 and Regulating the Action ok tiie same in Circuits that pass to Electric 
Lioiits or Electro Magnetic Engines." 

In my system of electric lighting I havo proposed in a previous Patent to 
regulate the pressure or electro-motive forco at the central station by varying the 
Strength of the field magnets around the induction bobbins connected to the main 
10 conductors. 

, An y rise or fall in the electro motivo forco due to putting on or off lamps is to be 
indicated by an electro meter. I find that an electro dynoinoter similar to that of 
Webber, but of high resistance, is an improvement upon the olectro meter, owing 
to its greater reliability. Two of such are used, and connected ncross the mam 
15 conductors in multiple arc. 

In my system a city is to be divided up into districts j in each district there is a 
central station, which' station is provided with sufficient motive power and electric 
generators to supply half a milo radius. , ._. 

At this station I employ, say, five engines, each of 250 horse power; each eng 
20 tuns by a belt a separate lino of shafting. On this shafting is bolted, say, 40 
electric generators, so that each ongino and its system of generators may bo con¬ 
sidered comploto within itself. 2 large rods of copper are convoyed in pm»% 
o all the generators, and connecting levers nro arranged so that any generator may 
„ P , a '? a nc, o»s and feed into tlio two main conductors. 

tlle generators when connected to the mainsi are connected in multiple aic, 
" nd the field magnet of every generator is so wound, or tlio pulleys upon its shaft 
80 made that by increase or docreime of speed, or by a weakening or strengthening 
[Price 4d.] 






A.D. 1880.—N° 33. 


Edison’s Tmpts. in Apparatus for Developing Electric Currents for Electric Lights. 

of the field mngnot tho electro motive forco of the induction mny bo adjusted to 
exactly tho flame electro motive force in all the machines. 

I employ several subsiduary electro generators belted on tho shaft of tho first 
engine, which aro all in uso, and tho currents from these machines are convoyed by 
leading wires to the field mngnet of all tho generators, and serve to keep a constant 5 
field. A second series of these subsiduary machines is connected to tho shaft of the 
second engine, and connected in duplicate so as to bo used in caso of emergency or 
in case the first ongino stops. A switch is provided for changing one subsiduary 
generator from one sot to another set, so that the chango can be mado gradually 
riio subsiduary generators are also arranged in multiple arc, but tho field mar-nets’ in 
of main line generators are so connected that there will be a row of, say, 10 raa°nots 
connected in series, and tlieso sots connected in multiple arc. Switches are provided 
whereby, say, 10 fiold magnets are disconnected at onee, tho induction bobbin 
having previously beon disconnected from the mains. 

For energizing the field magnets of tho subsiduary generators I uso a dynamo 15 
oleetric machine, tho current from which passes through tho field mngnots of all tho 
subsiduary generators either in series or in multiple arc. 

,. °' r cuit I place a largo numbor of resistance coils of large wiro, and sub¬ 

divided so that each has, say, ^ of an ohm. resistance. A wire between each 
resistance coil leads to a rotary commutator, which by being turned short circuits 20 
a greater or loss number of resistance coils, thus increasing or decreasing tho 
strength of the currents in the field magnets of the subsiduary generators; this in 
its turn increases or decreases tho strength of the current in tho indication bobbins 
between them, aud this current in its turn increases or decreases tho strength of 
the field mngnots of the main line generators, and cause a rise or fall in tho pressure 25 
or electro-motive force of the line currents, according as more or less onor«y is 
drawn from tho stations by putting on or taking off lamps or electric enginos.° 

Ihus I am enabled to cause a rise or fall in the pressure or electro-motive forco 
by turning of tho commutator handle. To indicato tho rise and fall of electro¬ 
motive force the operator at the commutator has boforo him tho electro dynometer, 30 
as well as several standard lamps, to indicate the rise and fall. 

Inis apparatus I proposo to placo in a separate room from tho main rooms con¬ 
taining the generators and engines, tho connection therewith being mado by wires, 
but the movements of tho commutator are transferred by genriug and shafts to 
large dials, one in the generator room and ono in tho engine room, so that tho 35 
station master may know the proper time to start up or stop down ono or more of 
the engines. It may sometimes happen in practice that from tho breaking of bolts 
or a wire or other causes that a generator will cense to supply electricity to the main 
lines, oven when the induction bobbin is intact; this will cause the currents from 
the other generators to pass through this generator, and perhaps burn tho wire. 40 
lo prevent this I interpolate a short wire in the induction bobbin circuit, mado of 
bismuth or other fusible metal, which will melt and break the circuit, and save tho 
wires of tho generator before too great a heat is reachod. 

Between each generator I placo a loose pulley supported by a gudgeon, to'which 
pulley the belt may bo shifted in case a generator is to be repaired when tho system 45 
of generators of which it is ono is in use. 

It is well known that at different parts of the main circuit outsido of tho 
generators electric engines almost similar to the generators may be placed for tho 
purpose of giving out power to the shafting. 

r several electro-magnetic engines giving varying amounts of power, 60 

from 20 horse to A. of a horse, may be worked in multiple arc Tho less tho power 
required the smaller the engine, and tho greater the power required tho finer the 
wire used, and I find that it is proforable to place tho greutest length of tho wiro 
and resistance upon tho fiold magnot. 

In using these electro magnetic onginos in multiple arc for running a sowing 55 
or . oth “ srn , al ! machino I arrango a switch for disconnecting the mnebino 
trom tho circuit, a belt to connect the motor with the sewing machine, using » 


Edison's Impts. in Apparatus for Developing Electric Currents fovEkdric Ligh ts. 

very small pulley on the motor and a largo pulley on the sewing machine so ns to 
allow of high speeds in tho motor. I regulate tho speed of sowing by a friction 
lever pressing on the driving pulley of the sewing machine, which lever being con¬ 
nected to tho foot rest may be pressed lightly or heavily on tho pulley of tho 
5 sewing machine, and thus increase or diminish its speed instantly or stop it 
altogether. The pulley of the motor being a friction pulley allows tlio motor shaft 
to revolve at a slower speed oven when the belt is stopped 

When tlio motor is arranged to pump water to a tank I use a float which, when 
the water becomes too low, closes a circuit and connects the motor to the main line 
10 nnd when the wntor is sufficiently high the float serves to disconnect tho motor 
from tho eloctno circuit. 

For running machine shops with these motors, and wiioro an even speed is 
required I arrange upon the shaft of the motor a governor working in the ordinarv 
manner, but which when the speed has reached a certain point causes a lover to 
15 open the circuit and disconnect the motor from the circuit. 

These motors can be worked upon tho same main conductors as the lamps. 








Edison’s Impts. in Apparatus for Developing Electric Currents for Electric Lights. 

SPECIFICATION in pursuance of the conditions of tlio Letters Patont filed bv 
tho said Thomas Alvu Edison in the Groat Seal Patont Office on tho 1st 
July 1880. 

Thomas Alva Edison, of Menlo Park, in the State of New Jorsoy, United States 
of America. » Improvements in Apparatus foii Developing Electiuc Currents 5 
and Regulating the Action of the same in Cikcuits that pass to Electrio 
Lights or Electro Magnetic Engines." 

In my system of electric lighting I hnvo proposed in a provious Patent to 
regulate the pressure or electromotive force at the central station by varying tho 
strength of tho field magnets around the induction bobbins connected to tho umin 10 
conductors, any rise or fall in the electro inotivo force duo to putting on or off 
lamps being indicated by an electrometer. I find that an electro dynamometer 
similar to that of Webber, but of high resistance, is an improvement upou the 
electrometer owing to its greater reliability. Two of such are used and connected 
across the main conductors in multiple arc. In my system a city is to bo divided 15 
up into districts ; in each district there is a central station, which station i'b provided 
with sufficient motive power and electric generators to supply half a mile radius. 

At this station I employ, say, five engines, each of two hundred and fifty horse 
power. Each engine runs by a belt a separate line of shafting ; on this slmftim' 
is belted, say, forty electric generators, so that each engino and its system of 20 
generators may be considered complete within itself. Two large rods of copper are 
in proximity to all tho generators, and connecting levers arc urranged so that any 
generator may be placed across uiid feed into tho two main conductors. All the 
generators when connected to tho mains are connected in multiple arc, and tho 
field magnet of every generator is so wound, or the pulleys upon its shaft so made, 25 
that by increase or decrease of speed, or by a weakening or strengthening of tho 
field magnet, the electro motive force of the induction may bo adjusted to exactly 
the same electromotive force in all the machines. I employ several subsidiary 
electric generators belted on the shaft of the first engine which are all in use, and 
the currents from theso machines aro conveyed by leading wires to tho field magnet 311 
of all the generators and serve to keep a constant field. A second series of these 
subsidiary machines is connected to tho shall of the second engine, and connected 
in duplicate so as to be used in case of emergency or in case tho first engine stops. 

A switch is provided for changing one subsidiary generator from one set to 
another set, so that tile change can be made gradually. Tho subsidiary generators 35 
are also arranged in multiple arc, but the field magnets of main line generators are 
so connected that there will be a row of, say, 10 imignets connected in series, and 
theso sets connected in multiple arc. Switches are provided whereby, say, ten 
field mngnots are disconnected at once, the induction bobbin having previously 
been disconnected from tho mains. For energizing tho field magnets of tho sub- 40 
sidmry generators I use a dynamo electric machine, tho current from which passes 
thioiigh the field magnets of all the subsidiary generators cither in series or in 
multiple arc. In this circuit I place a large number of resistance coils of huge 
wire and subdivided, so that each has, say, one fiftieth of an ohm. resistance. 

A wire between each resistance coil leads to a rotary commutator, which by 45 
being turned short circuits a greater or less number of resistance coils, thus 
increasing or decreasing tho strength of the current in the field magnets of tho 
subsidiary generators, this in its turn increases or decreases the strength of the 
current in the induction bobbins betweon thorn, and this current in its turn 
increases or decreases the strength of tho held magnets of the main line generator*, 50 
and causes a rise or fall in tho pressure or electromotive force of tho line currcnls, 
according us more or less energy is drawn from the stations by putting on or 
taking oil lamps or electric engines. Thus I am enabled to causo a rise or fall in 
the pressure or electromotive force by turning of the commutator handle. To 
indicate the rise and fall of electromotive forco tho operator at tho commutator has 55 
before him tho electro dynamometer, as well as several standard lamps, to indicato 


Edison's Impts. in Apparatus for Developing Electric Cu rrents for Electric Lights. 

the riso and fall. This apparatus I propose to placo in a separate room from the 
main rooms containing the generators and engines, the connection therewith being 
made by wires, but the movements of tho commutator are transferred by gearing 
and shafts to largo dials, ono in the generator room and one in tho ongino room so 
5 that the station master may know tho proper time to start up or stop down ono 
or more of the engines. It may sometimes happen in practice that from tho 
breaking of belts, or a wire, or other causes, that n generator will cease to supply 
electricity to the main lines, oven when tho induction bobbin is intact; this will 
cause tho currents from tho other generators to pnss through this generator and 
10 perhaps burn tho wire. To provont this I interpolate a short wire in tho induction 
bobbin circuit mndc of bismuth or other fusible metal, which will melt and break 
tho circuit, and save the wires of tho generator before too great a heat is reached. 
Between each generator I place a loose pulley supported by a gudgeon, to which 
pulley tho belt may be Bhiftcd in ease a generator is to be repaired when tho 
| system of generators of which it is one is in use. It is well known that at different 
parts of tho main circuit outsido of tho generators, electric engines almost similar 
to the generators may bo placed for tho purpose of giving out power to shafting. 
I find that soveral electro mngnetic engines giving varying amounts of power, from 
twenty horse to »/„ of a horse, may bo worked in multiple arc. Tho less tho 
I power required the smaller the engine, and the greater the power tho finer tho 
wire used, and I find that it is preferable to place the greatest length of tho wire 
and resistance upon tho fiold magnet. 

In .using theso electro magnetic ongincs in multiple arc for running a sowing 
machine gr othor small machine, I arrange a switch for disconnecting the inachino 
i from the circuit, a bolt to connect tho motor with the sewing machine,using a very 
small pulley on the motor and a largo pulley on the sewing machine, so as to 
allow of high speeds in tho motor. I regulate the speed of sowing by a friction 
lever pressing on the driving pulley of tho sewing machine, which lover being 
connected to tho foot rest may be pressed lightly or heavily on tho pulley of the 
l sewing machine, and thus increnso or diminish its speed instantly or stop it 
altogether; the pulley of the motor being a friction pulley allows the motor shaft 
to rcvolvo at a slower speed even when the belt is stopped. 

When this motor is arranged to pump water to a tank I use a float, which, when 
the water becomes too low, closes a circuit and connects' tho motor to tho main 
35 line, and when the water is sufficiently high tho float serves to disconnect the 
motor from the electric circuit. For running machine shops with theso motors, and 
where nn even speed is required, I nrrnngo upon tho shaft of tho motor a governor 
working in the ordinary manner, but which when the spoed has reached a certain 
point, cuuses a lever to open the circuit and disconnect the motor from the circuit. 
40 These motors enn be worked upon the samo main conductors as the lamps. 

Having now described tho nature of my said Invention and in wlmt manner tho 
same is or may bo performed, I declare that I claim as my Invention,— 

The method herein specified of regulating and controling the action of magneto 
electric generators and governing the electro motive forco throughout a system of 
15 conductors, in which system are included electric lamps or magneto electric motors, 
substantially ns sot forth. 

In witness whereof, I, the said Thomas Alva Edison, have hereunto set my 
hand and seal, this Fifteenth day of June, A.D. 1880. 

THOMAS ALVA EDISON. (l.s.) 

50 Witnesses, 

Ciias. H. Smith, 140, Nassau St., New York. 

Geo. T. Pincknev, „ „ 

LONDON: Fruit.*! by Gkui.uk Emu , hi. Kvuk uml Wtu.iam SrarmwouUK, 

Printers to tho Queim’H most Excellent Majesty. 

For Hor Majesty’s Stationery Office. 






A.D. 1880, lOi/t February. N° 578. 


Electric Lamps. 


LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in tho State of New 
Jersey, United States of America, for an Invention of " Improvement in 
Electric Lamps, and in the Method or Manufacturing the same.” 


PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at the 
Office of the Commissioners of Patents on tho 10th February 1880. 

Thomas Alva Edison, of Menlo Park, in the Slnto of New Jorsoy Unitod 
_ States of America. ■' Improvement in Electric Lamps, and in the Method 
5 of Manufacturing the same.” 


For an electric lamp I prefer to use an incandescing conductor of high resistance 
hermetically sealed in a glass chamber. ... , , 

Great difficulty has always been experienced in so sealing a gloss vacuum globe 
or chamber that a complete union of parts was had, and danger of opening or 
10 separation avoided. In all vacuum sealing of which I am cognisant ,there 1ms 
never been a complete union of tho parts where tho parts joined were attempted to 
be joined in vacuo. There might bo a union forming a tight joint lasting some 
indefinite time under ordinary conditions, yet critical examination would always 
reveal a lino showing incomplete juncture, where, undor tho influence of heat 


15 conditions present in an'eTcctricInmp.’an opening would occur. One part of my 
Invention therefore relates to a method of manufacturing electric lamps so that a 


One part of my 


stable vacuum may bo maintained therein. , ... , . , 

In manufacturing my lamps a glass bulb is formed with a long but small tube 
extending therefrom, by Y which the bulb is to bo attached to tho air pumps, and it 
20 is preferably curved so thnt sevoral may bo attached to one pump. 

Upon the opposite side from the tube is formed a supporting neck of a size 
sufficient to permit tho introduction through it into the body of tho bulb of the 

A piece of small tubing is formed with a round head at .one ond 
2o neck referred to, for receiving tho supporting and conducting wires of tho arc. Ihe 
lube, a little below this head, is enlarged to tho sizo of tho ncclc. f l f 

Upon tho head a part of tho glass whero the platinum wire pMsi mjbmeiot 
"bite enamel glass having a greater conducticity for heat than tho mam part of the 
vessel. The enamel glass through which tho platinum wires pass is then melted and 
[l'rice 8d.] 



















Edison’s Improvement in Electric Lamps. 


sealed around them by fusion, tlio glass extending somo littlo distance above tlie 
general plane of the head around tbo glass, or vice versa. On the outside of the 
bulb the platinum wires nro joined] to copper or aluminium wires which pass out 
through the lower or opon ond of the tubo. Clamps for holding tho incandescent 
conductor nro secured to the upper ends of tho platinum wires, and the incandescent 5 
conductor secured therein. Tho head is then passed into the neck until the lower 
edge of the neck and tho enlargement of tho tube below tho hend meet, when the 
two are there joined together by fusion. 

The lamp is now ready for exhaustion, and for this purposo it is attached by tho 
tubo referred to to an air pump. When tho proper degreo of vacuum has been 10 
reached the tube is closed by fusion at tho point of juncturo with tho pump, and 
the lamp removed from the pump. The tubo is then scaled by fusion at or near 
tho piano of tho bulb. There is now tho same degreo of vacuum upon each sido of 
this last seal that is in the bulb and in tho tube between tho two seals innde. 

The vacuum in the tubo is now destroyed, and tho tube again sealed just abovo 15 
the seal at or near tho plane of tho bulb ; tho vacuum in tho bulb is now protected 
by two sealings, the one in vacuo and one in air. I find that this double sealing 
makes a complete and perfect union of the parts, so that a stable vacuum may be 
maintained. 

In manufacturing these lamps I use within tho vacuum chamber only such JO 
materials as when subjected to influences within tho chamber consequent upon the 
light do not injuriously effect tho light. For instance, iron or steel under the 
influence of heat vaporize to a slight extent, and platinum in its ordinary state 
always contains somo air or gas. I therefore uso platinum or metals of that group 
prepared and treated by a process hitherto announced by mo, or aluminium may 25 
be used for the supporting clamps and for the metallic parts within the vacuum 
chamber. 

If a definite area of radiating surface bo raised to a definite temperature a 
definite amount of light is tho result, a definite electro motive force, or as I lmvo 
termed it, “pressure" of current is required, and tho conductors or rnnins arc 30 
proportioned to all those conditions. 

I have discovered that if the resistance of the light giving medium bo increased, 
its radiating surface remaining tho samo,-tho same amount of light will bo produced, 
but tho conductors may bo diminished in size proportionally to tho increase of 
resistance, much less proportionate increase of pressure of current however being 3» 
required. 

For example, let all the lamps in circuit have incandescent conductors of 100 
ohms, resistance each, and 1000 pounds of copper conductor bo used in the main 
conductors, and 100 volts, bo required to keep tho lights up. If now the radiating 
surfneo of each lamp bo unchanged, but tho resistance of each bo raised to 200 40 
ohms., 500 pounds of copper conductor will answer for main conductors, and 140 
volts, will be required to keep tho lights up to tho same point, hence by doubling 
tho resistance of the lamp one half of the prime cost of tho conductors will be saved, 
tho amount of energy expended remaining tho samo, about 3000 foot pounds being 
required to mnintain the light in cither case, which is entirely independent of the 45 
resistance. 

Another part of my Invention therefore relates to utilizing this discovery by so 
adjusting tho radiating surfaco resistance and pressure relatively to each other 
that great economy in conductors may result. In one form I increase the resistance, 
the resistance in tho light, by taking a filament of carbon long enough to give twice • 
the ordinary resistance, and doublo it upon itself, keeping tho two surfaces 
electrically apart. In this case tho contiguous sides radiate littlo if any light, each 
obscuring tho other, but I obtain tho increased resistance necessaiy to enable me to 
uso small conductors, _ . 55 

A number of arcs may bo connected togethor os a series in ono lamp, in '™ IC " 
ovent an incroaso of resistance (equal to number used) and of radiating surface 


s'SJSt A.D. 1880.—N° 578. 3 

_ Edison's Improvement in Elect ric Lamps. 

would bo secured with a proportionate dccreaso in tho amount of conductor 
necessary. 

As a necessary part of any practical system of electric lighting for domestic uses 
it appears to bo essential that an electric lamp should bo simplo in construction and 
5 complete within itself, requiring no skill in placing in position or in manipulation. 

To provido for this upon tho lowor ond of tho lamp, as described under tho first 
head, an insulating ring is secured, upon the opposito sides of which.are placed two 
contact springs, ono of the conductors leading from tho incandescent conductor 
being secured to each. 

10 A holder is mado by hollowing out a pieco of insulating material Bhaped or 
ornamented, ns desired, tho bottom boing fashioned so as to bo secured in any 
suiiablo support, say, a bracket or chandelier arm. On the interior of tho hollow 
(which is of a sizo to rcccivo the neck of the lamp) are two metallic pieces insulated 
from each other; to ono is fastened a conductor leading directly or indirectly from 
15 tho source of electricity, opposito the other piece, and upon tho exterior of tho 
holder is a metallic nut, to which the other main conductor leads. A screw passes 
through this nut, and may be made to impinge against tho interior plate so as to 
electrically connect the nut and plate. Tho main conductors may pass to the 
holder through ordinary gas or other tubing, and through tho bracket or chandelier 
20 arms, or in any other suitable way. 

From this description it is evident tlmt a lamp holder may be so mado that tho 
lamp may be placed in position in or removed from tho holder without any skill or 
manipulation of binding posts or fastening devices, and that tho current for 
lighting is turned off or on by simply turning the screw connecting one plate and 
25 tho nut. 

It is evident that the portion of the neck of tho lam]) entering tho socket may 
bo round or square, or many sided, or provided with a leather, lugs, or splines, tho 
holder being correspondingly hollowed out. 

It is also evident tlmt tho neck and holder may bn mado of such relative size 
30 tlmt the neck shall slide upon and over instead of within the holder. 

In a prior application, filed by mo on tho 10th November 1879,1 have stated how 
fibrous material capable of carbonization may bo coiled in a spiral in order that a 
largo resistance may bo had with comparatively small radiating surface. In an 
application, filed by mo on tho loth December 1879, I lmvo shown how an 
35 incandescent conductor of small radiating surfaco with largo resistance may bo 
inado of paper properly carbonized. 

I lmvo sinco discovered that an incandescent conductor of very high resistance 
in comparison to the radiating surfaco may bo mado of such natural vegetable 
fibres os nro cnpnblo of carbonization. I profor to uso the fibre of bleached mnnilln 
40 licmp, although nny vegetable fibres which are large, round, and filamentary, instead 
of cellular may bo used. In using these fibres I wind the ends with tissuo paper 
and then carbonizo thorn, tho tissue paper wrapping forming an enlarged end, 
which gives a good bearing for the supporting clamps. 









A.D. 1880.—N° 578. 


Edison's Improvement in Electric Lamps. 


SPECIFICATION in pursuance of tho conditions of the Letters Patent filed by 
the said Thomas Alva Edison in the Great Seal Patent Ollice on the 10th 
August 1880. 

Thomas Alva Edison, of Menlo Park, in tho State of New Jersey, United 
States of America. “ Improvement in Electric Lamps, and in the Method 5 
of Manufacturing the same.” 

For an electric lamp I prefer to use an incandescent conductor of high resistance 
hermetically scaled in a glass chamber. 

Great difficulty lias always been experienced in so sealing a glass vacuum globe 
or chamber that a complcto union of tho parts was had, and danger of opening or 10 
separation avoided. 

In all vacuum scaling of which I am cognizant there 1ms never been a complete 
union of tho pnrts where the parts were attempted to be joined in vacuo, There 
might be a union forming a tight joint lasting an indefinite time under ordinary 
conditions, yet critical examination always revealed a line shewing incomplete 15 
juncture, when under the influence of heat or conditions present in an electric lamp 
an opening would occur. . 

One part of my Invention therefore relates to a method of manufacturing lamps 
so that a stable vacuum may bo maintained thcroin. In manufacturing iny lamps 
a glnss bulb is formed with a long small tubo extending therefrom by which the -0 
bulb is to bo attached to the air pump, and it is preferably curved so that several 
may bo attached to one pump. Upon the opposite sido from the tube is formed a 
supporting neck of a size sullicient to permit tho introduction through it into the 
body of the bulb of the carbon arc. A piece of tubing is formed into a round ^ 
head at ono end, smaller than tho neck referred to, for receiving ihe supporting and -a 
conducting wires of tho arc. The tube a little below this head is made as largo as 
the neck. A part of tho head where the platinum wires pass may be formed o 
white enamel glass having a greater conductivity for heat than the main part o 
tho vessel, or it may be of plain glass. Tho gloss through which the platinum wires 
pass is molted and sealed around thorn by fusion, tho glass extending some litt e 
distance above the general surface of tho head around tho wires, or vice versa, on 
the outside of the bulb. _ . 

Tho platinum wiros are joined to copper or alluminium wires which pnss ou 
through tho lower or open end of the tube. 1 nf 35 

Clamps for holding tho incandescent conductor nrc secured to the upper ends o 
the platinum wires, and tho incandescent conductors secured therein. The head » 
then |iassed into the neck until tho lower edge of tho neck and the enlargement, 
the tubo below tho head moot, and tho two arc there joined togethor by fusio • 
Tho lamp is now ready for exhaustion, and for this purpose it is attached Dj i 
tube aforesaid to an air pump. After the proper dogreo of vacuum has ei 
reached tho tubo is closed by fusion at tho point of juncture with the pump.*«* 
the lamp romovod from tho pump. Tho tube is then sealed by fusion at or n 
tho plane of the bulb ; there is now tho same degree of vacuum 11(1011 each si 
tho last seal. The vacuum in tho tubo is now destroyed, and tho tubo again set 
just abovo tho seal nt or near tho plane of the bulb. The vacuum in tho1 Du • 
now protected by two sealings, ono in vacuo and one in uir. I find tlm 
doublo sealing makes a complete nnd perfect union of tho parts, so that 0 s 
vacuum may bo maintained. . .„], 

In manufacturing these lamps T tiso within the vacuum chamber only 8 .j 
material ns when subjected to influences within the chamber consequent upon 
light do not afreet the light. For instance, iron or steel under tho induce. 
heat in a vacuum vaporize to a slight oxtent aud form carburet of iron,' 


A.D. 1880.—N° 578. 


_ Edison’s Improvement in E lectric Lamps. 

platinum in its ordinary stato always contains some air. I thorofore use platinum 
or metals of that group prepared nnd treated by heat in vacuum, as heretofore 
announced bv mo, or clso aluminium for tho supporting clamps and for all metallic 
parte within tho vacuum chamber. 

5 If a definite area of radiating surface bo raised to a dofiDite temperature a 
definite1 amount of light is tho result, a definito electro motivo forco of electricity, 
or, ns I have termed it, " pressure ” of current being required therefor, the conductors 
or mams being proportioned to all tlieso conditions. 

I have discovered that if tho resistance of tho light giving body bo increased, its 
10 radiating surfneo remaining tho same, tho same amount of light will bo produced 
but tho conductors may bo diminished in size proportionally to the increase of 
resistance, much less proportionate incrcaso of pressure of current however being 
required, hor example, if all the lamps in circuit liavo incandescent conductors of 
ono hundred ohms, resistance, each then ono thousand pounds of copper conductor 
15 should lie used in tho main conductors, nnd one hundred volts, will be required to 
maintain tho lights. If now tho radiating surface of each lamp bo unchanged, but 
llio resistance of each bo raised to two hundred ohms., five hundred pounds of 
copper conductor will answer for main conductors, ono hundred and forty volts, 
however being required to keep the lights up to tho same point, so that by doubling 
20 the resistance tho primo cost of ono half tho conductors is saved, tho amount o°f 
cnorgy exponded remaining the snmo, about three thousand foot pounds being 
required to mnintain the light in either case, which is entirely independent of the 
resistance. 

Another part of my Invention therefore relates to utilizing this discovery by so 
25 adjusting the radiating surfaces, resistances, and pressure relatively to each other 
that great economy in conductors may be obtained. In ono form I increase the 
rcsjstnuce by taking a filament of carbon long enough to givo twice tho ordinary 
resistance, and doublo. it upon itself, keeping tho two surfaces electrically apart. 
In this case the contiguous sides radiate but little light, as each obscures the otlior, 
30 hut I obtain tho increased resistance necessary to enable mo to uso the smaller 


A number of arcs may be connected togotlior as a series in one lamp, in which 
event there is an increase of resistance equal to tho number used, and radiating 
surfaces nro secured with a proportionate dccreaso in the amount of conductor 
35 necessary. As a necessary part of any practical system of electric lighting for 
domestic uses it is essential that the electric lamp should bo simple in construction, 
and complete within itself, requiring no skill in placing in position or in ninnipu- 

To provide for this an insulating ring is secured upon the lower end of the neck 
™ °f tho lamp, nnd upon tho opposito side of this ring are placed two contact springs, 
one of tho conductors loading from tho incandescent conductor being secured to 
each. A cup shaped holder is made of insulating material, ornamented as desired, 
the bottom being fashioned bo ns to be secured in any suitablo support, such as a 
bracket or chandelier. On the interior of tho cup, which is of a size to receive tho 
45 neck of the lamp, are two metallic plntos opposite to but insulated from each other. 
To ono is fastoned a conductor lending directly or indirectly from tho sourco of 
electricity, and upon tho oxterior of the holder is a metallic nut, to which tho other 
main conductor loads. A screw passes through this nut, nnd may be mndo to 
... ,,n P’u>go against tho otlior motallic pieco, so as to electrically connect the nut and 
cu plate. Tho main conductors may pass to tho lioldor through ordinary gas or 
other tubing, and through the bracket or chandelier arm, or in any other suitablo 
way. 

From this description it is evident that a lamp holder may he so made that tho 
lamp may be placed in position in or removed from tho holder without any skill 
a or manipulation of binding posts or fastening devices, and that the current for 
fighting is turned off or on by simply turning tho screw that presses upon ono of 
tho plates. It is evident that tho portion of the neck of tho lamp entering the 








Specification. 


A.D. 1880.—N° 578. 


Ellison’s Improvement in Electric Lumps. 


socket may bo round, or square, or many sided, and provided with a feather, lugs, 
or spliner, the holder being correspondingly hollowed out. It is also evident that 
the neck and holder may bo made of such relative sisto that tho neck shall slide 
upon and over instead of within the holder. In a prior application for Letters 
patent I have stated how fibrous material capable of carbonization may he coiled 5 
in a spiral in order that a large resistance may bo hud with comparatively small 
radiating surface. I have also shown how all incandescent conductor of small 
radiating surface with largo resistance may bo made of paper properly carbonized. 

I have sinco discovered that an incandescent conductor of very high resistance in 
comparison to the radiating surface may be made of such natural fibers os are 10 
capable of carbonization. I prefer to use the single fiber of blenched mnnilla 
hemp, although any of the fibers which nro large, round, and filamentary instead of 
cellular may bo used, as hereafter set forth. In using these fibers I wind the ends 
with tissue paper niul then carbonize them, tho tissue paper wrapping forming an 
enlarged end, which gives a good bearing for the supporting clamps. 13 

Figs. 1, 2,11, 4, & 5 illustrate tho method of manufacturing my improved lamp, 
showing the steps therein successively. , . , , 

A piece of tubing the size of c is taken, on which is blown or otherwise forme, 
tho bulb b, whoso upper portion is drawn out into the tulio h curved so that several 
bulbs may bo attached to ono air exhausting pump. The part c is left unchanged -U 
in order to form a supporting neck for tho lamp ; in forming this from tubing 
however the lower end is often drawn out as shown in Fig. 1; this small end a 
removed on the line x, x, leaving the globo neck and tube ns shown in lig. - ! 

/ is a piece of glass tubing of a size somewhat less than c ; upon its upper end is 
formed tho bulb d and the two seals p, p, for tho wires. Below <1 tho enlargement c 25 
is formed in the tube /, its exterior diameter being the same or nearly so as that 
of c. Platinum wires w, w, joined to conductors 1, 2, are passed through openings 
in tlie projections p, p, which projections are then fused by heat around the wires 
to, 10, so as to seal the wires hermetically in the gloss, said seals extending around 
the wires above the general surface of tho bulb d. Chimps It', h', aro attached to J 
the wires, nnd tho incandescent conductor fastened in tho clamps. It is to be here 
remarked that the clamps or wires within the globo must be of some material not 
so affected by any influences existing within the globe when tho proper vacuum 
has been attained as to interfere with the light or its proper dissemination, l 
iron be used it is so acted on that it is gradually destroyed with an ensuing deposit 
on tho glass obscuring the transparency of the globe, nnd also acting on tho carbon, 
uniting with it, nnd finally destroying it. In order to prevent this, and to guar 
against any injurious influences whatever, the clamps Id, Id, nnd wires within «j 
globe should bo of platinum or some metal or metals of the platinum group, tree e. 
by the vacuum and heating process described by mo in a prior application lor 
Letters Patent. Tho arc a and bulb d are inserted in tho neck c until the end *, 
of tho neck c rests against tho enlargement e, when the two aro securely an 
hermetically joined by fusion of the glnss at that point. Tho tube c is large ono „ 
to allow the carbon arc, which is slightly flexible, to pass through it. 1 ho temp . 
attached by the tube h to an exhaust pump of any suitable character, and alter ^ 
proper degree of exhaustion has been reached tho tubo It is scnled by fusion o 
glass at i and removed from tho pump, and a second seal i is mndo m tlic i 
immediately above tho globo b. This last sealing is mado entirely in vacuo, 
the degree of vacuum in b and in h between l nud i is tho same. I ot - 50 

however that a perfect nnd durable seal cannot bo made when all tho porn 
tho glnss which unite to form tho seal aro in a vacuum whon tl.o »e..l «* . ’ 

hence tho seal i at tho end of the tubo It. Tho tubo It is now sea .•J 

fusion at ill, or it may bo broken off at m and a drop of molten glass placed • 
and tho parts molted to form tho seal. Tho seal I 1 , Fig. 5, is therefore tho 1 55 

two sealings, at l in vacuo, and at m in air. , . . i|, e 

I have found that such a seal is lasting under all conditions, nnd that } 
method hero indicated a globo is so constructed and sealed that a vacuum pe > 


A.D. 1880.—N° 578. 7 


Edison's Improvement in Electric Lamps. 

stablo is maintained therein. Tho wires 1 & 2 for attachment to devices for com¬ 
pleting tho circuit pass out of tho end of tho tubo f and in order to prevent their 
accidental crossing or displacement a plug 11 of cork, piaster of Paris, or other 
insulating material is put in the end of/securing the wires therein. 

5 Figs. G, 7, 8, 0, 10, and 11 show modifications in which tho resistance of the 
incandescent arc is increased. In Fig, G b is tho enclosing globo. Several incan¬ 
descent conductors a, each of tho standard resistance, aro united at their ends in a 
scries by conducting clamps h, the terminal ends of tho series connecting to 
clamps Id, Id, to which are attached the wires tv, to. The series nro supported 
10 upon il in circular form by wires or other supports 3, 3. In this case tho current 
entering by 1 traverses ono carbon nnd passes by chimp k to the next, and so on 
through tho series to conductor 2. Five of these carbons are shown in Figs. G nnd 7. 
As each incandescent portion a is of stnndurd resistance, and gives a standard light, 
tho object of this arrangement is to group a number of such lights, and to light a 
15 much larger area than ono light would, at the snme time the total resistance of tho 
lamp being proportionately increased the size of the conductors or street mains is 
proportionately lessened, there being consequently grout economy in the laying 
thereof, and tho number of street lamps required being lessened it is practicable to 
light thinly settled highways nnd streets. 

20 In Figs. 9, 10, and 11, a strip a of carbonized material is employed of stnndard 
resistance for a given length, but of twice tho ordinary length, nnd the same is 
doubled upon itself. At tho point of bending back an insulnting block 0 is iutro- 
duced, so that the folded carbonized strip is kept apart. To the free ends nro 
attached tho clamps Id, Id, nnd conductors w, w. Each inner contiguous surface is 
25 partinlly hidden by tho other, so that the outer surface is tho portion that radiates 
light, nnd this is to be equal to the total surface of an ordinary or undoubted carbon; 
but the increase of length has doubted tho resistance, hence there is a doublo 
resistance with little chnngo in tho radiating surface. This doublo resistance 
however ennbles a smaller conductor to bo used, tho amount of metal in this 
30 instance being diminished ono half. This ability to diminish the amount of metal 
in conductors is of great importance, ns in many instances, notably in thinly 
settled localities, it may determine tho practicability of a system of electric lighting. 
It also enables localities far distant from a central station or source of electric 
energy to bo supplied with electric energy for purposes of light and power when 
35 under ordinnry conditions, or under conditions which have usually existed, tho 
first cost of conductors nnd tho cost of maintenance would prove insurmountable 
obstacles. 

An incandescent conductor of very high resistance in propoition to its radiating 
surface may be made of any natural fiber capable of carbonization, especially such 
40 as nro large und filamentary instead of cellular. A preferable one for this purpose 
is a single fiber of bleached mnnilla hemp. A liber is taken, its ends wound with 
tissue paper and then carbonized, tho carbonization uniting tho fiber nud paper 
wrapping, tho latter forming an enlarged end, which gives a good bearing for the 
supporting clamps. Figs. 12 nnd 13 show my lamp manufactured as hereinbefore 
45 described with additions and modifications, rendering it a separate and complete 
urticlc adapted for attachment to a suitable support. Upon tho lower end of tho 
part 0 is secured a cylinder q of any suitable insulating material, provided on 
opposite sides with metallic springs or contact pieces 13, 14. l'rom the clamps 
Id, Id, which hold and support the incandescent arc a, the conductors; 1, 2, lead to 
60 tho contact pieces 13,14, adapted to complete the electrical circuit when tho lamp 

is placed in position in tho holder hereafter described. 

This construction forms a separate electric lamp, which may readily bo removed 
from or placed upon or within a suitable holder, tho act of placing tho lamp in 
position completing without adjustment or attention the necessary connection of 
55 tho circuit to tho light giving portions, r is a socket or holder for receiving the 
the lamp. It is made of suitable insulating material, shaped and ornnincntou as 
may bo desired, rccoiving and supporting tho neck of the electric lamp, and 







8 A.D. 1880.—N° 678. 


Edison’s Improvement in Electric Lamps. 


fashioned at ono end so as to be fastoned onto a gas fixturo or other suitable 
support, os shown. Tho cylindrical cup or socket for tbo lamp is at the top, and 
a scrow threaded nporturo in the base allows tho holder to be attachod to a 
standard, a bracket, or a chandelier arm t. Upon the interior aro tho metallic 
plates u, v, insulated from each other. Upon tho exterior of tho holder is u motailic 5 
nut s in which works tho metallic scrow y. A conductor 6 leads to the pinto u, 
and a conductor 0 to the nut s; upon turning tho scrow y electric connection 
between tho plato v and nut s is either completed or broken dependent upon tho 
direction of turning. Tho conductors 5, C, lend directly or indirectly from tho 
source of electricity, and may bo placed inside of gas or other suitablo pipes or 10 
tubing, ns shown in Fig. 12, or they may be brought to tho lamp in any convenient 
mnnnor. From this it may bo seen that if the lamp be placed in tho socket r, as 
shown in Fig. 12, one spring 13 bears against and forms electrical contact with ono 
plate, say u, while tho other spring 14 bears against and forms electrical contact 
with the other plato v. 15 

If the screw y he turned so as to impinge firmly on plate v a complete circuit is 
formed via wire 5, plato u, spring 13, wire 2, incandescent arc a, wire 1, 
spring 14, plato v, screw y, nut s, and wire C, tho maximum light, a dim light, or 
no light, being duo respectively to a fine contact, a slight contact, or no contact 
between v and y. 20 

From the description it is evident that tho lamp is an article complete in itsolf, 
capable of being placod in position for use without any attention or adjustment 
While I have shown contact springs upon the cylinder q or tho neck of tho lamp, 
and contact plates upon tho interior of the socket or holder, it is evident that tho 
relation could be reversed, tho plates being placed on the neck of tho lamps, and 25 
the springs in tho socket without departing from the spirit of my Invention, 
or requiring any further Invention. It is also evident that the lamp can bo so 
constructed that the neck will embrace tho holder instead of being placed thorcin. 

What I claim as my Invention is,— 

First. The method of forming electric lamps, consisting in separately forming the .10 
enclosing globe and tho supporting bulb for tiio incandescent conductor, attaching 
the wires and incandescent conductor thereto, nnd then hermetically uniting tho 
parts prior to the formation of the vacuum, substantially ns set forth." 

Second. The method of hermetically sealing a vitrified vacuum chamber, which 
consists of first sealing in vacuo and then sealing in tho air, substantially as 33 
described. 

Third. Tho clamps and wires made of platinum or motals of tho platinum group 
or conductors of electricity not affected by influences within the lamp, substantially 
as described. 

Fourth. In a system of generation, distribution, and translation of electricity for 40 
purposes of light, the method of diminishing the amount of metal required in a 
given length of main conductors by increasing the resistance of the lamps, 
substantially as described. 

Fifth. An incandescent conductor formed of sovornl separata conductors joined 
together, substantially ns sot forth. 45 

Sixth. An incandescent conductor formed of a long strip doubled upon itself, so 
as to increaso tho resistance nnd maintaiu a given radiating surfaco, substantially 
as sot forth. 

Seventh. An incandescent conductor formed of a singlo carbonized fiber, 
substantially as described. w 

Eighth. An incandescent conductor having a body formed of a single fiber with 
enlarged ends mado of paper wrapped upon tho ends of the fiber and carbonized, 
substantially as set forth. 

Ninth. A separata electric lamp adapted to bo readily removed from, or placed, 
or replaced upon or within a suitable holdor, substantially as herein described. 55 

Tenth. Tho combination of a separata removable electric lamp and a suitable 
holder, substantially as heroin described. 


A.D. 1880.— N° 678. 


_ Edison’s Improvement in Electri c Lamps. 

Eleventh. The combination of a sopnrato removable lamp, a suitable holder, and 
electric conductors, which comploto tho circuit whon desired to said lamp, but are 
not attached theroto, substantially as herein described. 

Twelfth. An doctric lamp consisting of a gloss globe, substantially of ono pieco 
5 of glass, hermetically sealed, nnd enclosing in a vacuum material capable of being 
rendered incandescent by an electric current, and provided at its base with contact 
pieces, substantially ns herein described. 

Thirteenth. Tho combination in an electric lamp of a glass globe enclosing in a 
vacuum material capable of being rendered incandescent by an electric current, an 
10 insulated base. Bpring contacts, and conductors thorofrom to the incandescent 
material, substantially as heroin described. 

Fourteenth. A socket or bolder for electric lamps consisting of an insulating 
cylinder formed to receivo and support tho lamp, and provided with two contact 
plates and a circuit controling device for coutroliug the circuit to one of tho contact 
15 plates, substantially as herein set forth. 

Fifleontli. The combination with a bracket or chandelier arm of a socket or 
holder adapted to receive and support an electric lamp, substantially ns herein set 
forth. 

Sixteenth. Tho combination of a holdor, bracket, or cliandelior arm with a socket 
20 or holdor adapted to bo received thereon, nnd to receive and support an electric 
lamp and conductors passing through tho arm to contact plates in the holder, 
substantially as herein set forth. 

Seventeenth. Tho combination with a socket or holder provided with suitablo 
contact plates of a lamp provided with corresponding contact springs upon its 
25 cxtciior, substantially ns herein set forth. 

In witness whereof, I, the said Thomas Alva Edison, have hereunto set my 
hnnd and seal, this 29 day of Juuo, A.D. 1880. 

THOMAS ALVA EDISON. (l.s.) 

Witnesses, 

30 S. L. Griffin, 

Frank JlVLAuauuN. 

















A.D. 1880, nth February. N° 599. 


Anaesthetic Compound. 


LETTERS PATENT to William Robert Lake, or the Firm or llaxeltii.o, Lake, 
& Co., Patent Agents, Southampton Buildings, London, for an Inventi 
“An Improved Anesthetic CoMrouND.” A commumcation trom aurouu 
by Thomas Alva Edison, of Menlo Park, Now Jersey, United States oi 
America. 


PROVISIONAL SPECIFICATION left by the said William Robert Luke at the 
Office of the Commissioners of Patents on the 11th February 18SU. 

William Roiieut Lake, of the Firm of Haseltinc, Lake, & Co., Patent Agents, 
Southampton Buildings, London. " An Improved Anestueti Jersey 

communication from abroad by Thomas Alva Edison, of Menlo Park, New Jersey, 
United States of America.] _ , 

The object of this Invention is to provide means for producing anaesthetic effects 
upon the nerves by external application for obtaining relief from p 

° r Sm S:ri,w7nUofeoluL e ; first, in providing V^^lc^Twhirtve 
of the most powerful chemical substances which act amesthotically and which 

dissolving the said substances, which menstruums shall ha '’ . .. , ti 

upon each other or upon the said substances other than to eHect thcii bO UUon 
The object of placing in one compound all of the most powerful 
pounds which net uiuesthetically is to ousure that it one doe m-oduce the 

may, as it is woll known that a certain anaesthetic may in one case produ « 
effect, but in another case will not produco amestliesia, while an infonor amosttietic 

’KsraT.tfa a. LTS“:.i“ 

compounded according to the formula given below, that in some a y 
one anaisthotie (luickons the action of the others. „i.i nr „i 

The ingredients which I use in practising this Invention aro hydra e o chlorah 
chloroform, other, nitrate of amyl, morphia, opium, camphor, alcohol, oil 
{Price 4d.] 

























2 A.D. 1880.—N° 599. 


Luke's Improved Anasthctic Compound. 


peppermint, salicylic acid, and oil of cloves. Tlio alcohol, otlior, and chloroform 
act anmsthctically as well as being menstruuras for dissolving the other ingredients. 

The preferablo proportions aro as follows, that is to say:— 

1 o7„ of hydrate of chloral, 4 ozs. of alcohol, 2 ozs. of chloroform, 2 ozs. of 
camphor, 2 minims of oil of peppermint, 2 minims of oil of cloves, 3 ponnywoighls 
of salicylic acid, 3 pennyweights of nitrate amyl, 2 pennyweights of morphia 
sulphate, 2 ozs. of other. 

But the proportions may bo varied, and inoro of one substanco and less of tho 
others may be used; the amount of the different substances should bo such that 
the menstruums will dissolve them. Other amesthctics may bo added to this com¬ 
bination, or ono or more of tlioso mentioned may be dispensed with, but to meet all 
of tho various conditions of the human nerves it is better for tbo compound to 
contain all of the most powerful anmstheties, to tho end that should one, two, or 
three, or more fail to act while npplied separately, thero must bo one or more 
among the whole which will produco relief, especially when they are commingled 
and applied together. 

This preparation is designed for external application only. 


Lake’s Improved Anasthctic Compound. 


SPECIFICATION in pursuance of tho conditions of tho Letters Patent filed 
by tho said William Robert Lake in tho Great Seal Patent Ofiico on tho 
10th August 1880. 

William Robert Lakh, of the Firm of Haseltino, Lake, & Co., Patent Agents, 
5 Southampton Buildings, London. “ Am Improved Anesthetic Compound.” A 
communication from abroad by Thomns Alva Edison, of Menlo Park, Now Jersoy, 
United States of America. 


The object of this Invention is to produce anicsthotic effects upon the nerves 
by external application to obtain relief from pam until nature or medicine may 
10 olfcct a cure. 

Tho said Invention consists, first, in a compound of a number of the most 
poworful chemical substances which act anrosthetically and which liavo no effect 
upon each other. 

If further consists in placing in such compound various menstruums for dissolving 
15 the said substances, which inonstruums shall have no chemical action upon each 
other or upon tho said substances other than to effect their solution. 

The object of placing in one compound all of the most powerful chemical 
compounds which net anmsthetically, is to onsure tho action of one of them, that is to 
say, if one does not act tho others may, as it is well known that a certain nmesthetic 
20 may in one case produce the desired effect, but in another case will not produco 
nmesthesin, while an inferior aiuesthetic will produce nmesthesia. 

Furthermore, it is believed from tho surprising effects of this preparation when 
compounded according to tho formula given bolow, thnt in some manner tho action 
of ono anicsthetic quickens tho action of the others. 

25 The ingredients which I use aro hydrate of chloral, chloroform, ether, nitrate of 
amyl, morphia, camphor, alcohol, oil of peppermint, salicylic aciu, and ou ot cloves. 
The alcohol, ether, and chloroform act aniusthetically, and also as menstruums foi 
dissolving tho other ingredients. 

The proportious I prefer to uso nro ns follow, that is to say One onneo of 
30 hydrate of chloral, four ounces of alcohol, two ounces of chloroform, two ounces ot 
camphor, two minims of oil of peppermint, two minims ot oi of doves, three 
pennyweights of salicylic acid, three penny weights of nitrate amyl, two pennyweights 
of morphia sulpliato, two ounces of ether. 

But these proportions may bo v« 


.of one substance and less of the 

35 others may'bo used; the amount of the different substances should bo such that 
tho menstruums will dissolve them. Other nmesthetic may b uldt I to this 
combination, or ono or more of tlioso mentioned may bo dispensed with, but to 
meet all of tho various conditions of the human nerves it is hotter that the 
compound slio, Id co t n all of tl o i o t \ o c f 1 c ti et e to tl o e id that 
40 should one, two, three, or more fail to act while applied separately, here must 
bo uno or more among tl.o wholo which will produce relict, especially when they 
are commingled and applied togother. 

I prefer menstruums which are also anaesthetics, but other n.enstruums w, servo 
tho purpose of this Invention provided they do not combine chemically ruth tho 
45 other ingredionts used. _ , 

This preparation is designed for oxtcrnal application only. 















A.D. 1880.—N° 699. 


Lake’s Improved Anaethetic Compound. 

■ Having thus fully described the said Invention as communicated to mo by my 
foreign cdrres|iondciit and tho niannor of performing tho same, I wish it under¬ 
stood that I claim,— 

The medicinal preparation compounded substantially as nbovo described. 

In witness whereof, I, the said 'William Robert Lake, have hcrounto set my 5 
hand and seal, this Twenty nintli day of July, in the year of our Lord 
One thousand eight hundred and eighty. 

W“. ROB T . LAKE. (L.s.) 





















A.D. 1880, 11 th February. N° 602, 


Utilization of Electricity for Light, Heat, and Power. 


LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in the State of 
Now Jorsoy, United States of America, for an Invention of “ Improvements 
nr tjie Utilization of Electricity for Light, Heat, and Power, being 
an Improved System and Means for the Generation, Regulation, 
Distribution, Measurement, and Translation of Electricity into 
Light, Heat, or Power.” 


PROVISIONAL SPECIFICATION left by the said Thomas Alva Edison at tho 
Office of the Commissioners of Patents on the 11th Fobruary 1880. 

Thomas Alva Edison, of Menlo Park, in the State of New Jersey, United States 
of America. “Improvements in the Utilization of Electricity for Light, 
5 Ueat. and Power, being an Improved System and Means for the Generation, 
Regulation, Distribution, Measurement, and Translation of Electricity 
into Light, Heat, or Power.” 

Tho object of this Invention is to so arrange n system for tho genoration, supply, 
and consumption for either light, heat, or power, or either or all, of electricity that 
10 all tho operations connectod therewith requiring especial care, attention, “know¬ 
ledge of tho art shall ho performed for many consumers at stations, leaving the 
consumer only tho work of turning off or on tho supply, as may ho dos.redj m other 
words to so contrive means and methods that electricity may ho supplied for 
consumption in a manner analogous to tbo system for the supply of gas and water 
15 without requiring any greater core or technical knowledge on tho part of the 
consumer than does th! use of gas or water, in order that economy, reliability, 

one district, or if tho extent of territory makes it desirable may ho divided into 

20 80V Inmh district I provide o central station, at which aroj 

motor or sovcral motors, dependent upon the amount to to supplied, generators 
or moans for converting tbo prime motive power into y» , , . 

determining and regulating tho amount of (dectneity generated and supplied, m 
25 order that a constant pressure of electricity v so to speak) may P P- 

Tho prime motors are any suitable engines, steam or watcr and " ' v ided w tU 
of two or more ore provided os may ho necessary, each of which is piovidod with 

[Price 8&] 








Edison'a Impts. in the Utilisation of Electricity for Light, Ileal, and Power. 

its own system of slmfting and belting driving n number of magneto electric 
machines, tho number actuated by ono prime motor being hereinafter tormed a 
battery. . 

It is to bo noted, as is also shown in previous applications for Patents mndo by 
mo, that X make my field of force magnets exceedingly long, and of nn extremely 5 
large mas9 of metal in proportion to tho mass of inotnl in tho revolving armature 
carrying tho generating coil. By this extra length, as tho mngnotic tension 
at tho polos increases with their distance apart, there is secured at tho polar 
extensions acting upon tho coils in tho Hold of force a much greater magnetic 
intensity, or so to speak, a greater motive force or pressure, causing consequently 10 
the generation of a greater amount of energy in tho coils operated on than would 
result from the use of shorter magnots, oven though tho samo mass of metal were 
used therein. By this elongation of tho cores I am enabled to disponso with 
numerous convolutions or layers, one layer of wire being sufficient, whereby tho 
resistance of the mncliino is largely diminished. The largo mass of metal in there 15 
magnets is magnetically saturated by a weak current passing around them. It 
takes this weak current a long time to bring this mass of metal up to tho point of 
practical maximum magnetic intensity, but once brought to that point tho weak 
current readily keeps them there, while with a shorter magnet a stronger current 
would more speedily magnetically saturate them ; this stronger current would still SO 
bo required to keep them so saturated. 

If the coils of tho field of force magnets and tho generating coils wore included 
in one circuit, and all tho currents generated were passed through tho field magnet 
coils, a very much greater amount of current than necessary for tho maintainunce 
of a practical magnetic maximum in the field of force magnots would be passed 25 
around them, and tho coils acting as resistances to tho energy in excess of that 
required to mngnotiso tho magnet to its practical maximum would causo a great 
waste of electric energy ; hence I prefer to keep the field of force magnets and the 
generating coils separate, and that one mncliino in each battory (which nracliiuo 
may bo termed tho battery field of force generator) bo used to supply tho requisite 30 
energy to the field of forco magnets of tho other machines in such battery (which 
may be termed tho supply generators). 

The coils of the field of forco magnets are connected as a series in a multiplo arc 
in ono circuit, while tho generating coils of the supply generators of each battery 
are all connected in a multiplo arc to tho main conductors (though for specinl 3o 
purposes thoy may bo connected as a series). 

This will give great economy, as the per cent, of tho entire current generated in 
each battery absorbed in keeping up the magnetic maximum in tho field of force 
magnets, when it is furnished by one special machine of tho battory, the number 
given it to feed being properly calculated, being less than when a portion of tho 4# 
current generated in each machine is absorbed in its own field of forco magnets. 

Where a single battory of machines is used it is preferable, in view of what has 
been hereinbefore stated, that tho current for tho coils of the field of force magnets 
of tho field of force generators of tho battery bo supplied by a small galvanic 
battery, but if more than ono battery of machines bo used tho Sold of forco 4 
generators of all tho batteries are fed from one or more primo field of force 
generators connected in a multiplo arc or in a series, tho field of forco magnots oi 
tho prime field of forco generator or generators used being kept magnetically 
saturated by a weak galvanic battery current, as boforo sot forth. For instance, 
a weak galvanic current supplies tho field current necessary for ono primo field 01 
force generator, which in turn feeds tho field of force magnots of tho field of force 
generators of ton batteries of twenty or thirty machines, the ultimate effect in tuo 
generation of currents depending upon (ns ono important factor) tho tension of tno 
galvanic current sent through tho field of force coils of tho primo field of force ^ 
generators. _ . 

This primo field of forco generator may howovor bo a dynamo electric roncbino 


Edison’s Impts. in the Utilisation of Electricity for Light, Ilcat, and Power. 


At the control station all tho supply generating coils' or batteries thereof aro 
connected to conductors on tho multiplo arc system, and from those conductors nt 
5 tho station main conductors (which for convenience may bo called simply tho 
mains), connected thereto on tho multiplo arc system, lead in any and all desired 
directions, convoying tho onergy to tho points where work either by translation 
into light or motive powor is to ho done. 

In order to give a bettor understanding of tho method of regulating what for 
10 convenience may be called tho pressure of tho cuiTent through tho entire system, 
I will here state that all tho devices for tho transmission of electricity into work 
are arranged on the multiple are system, each device being in its own derived 
circuit, tho effect being in substnneo to give each a circuit from tho generating 
source independent of the circuit of all tho other devices; ns a resultant it follows 
15 thnt the greater tho number of transmitting devices brought into circuit, tho less 
the totnl resistance of the current. 

For instance, I prefer my lamps should be of about 100 ohms, resistance, then if 
one lamp only bo in circuit there is a resistance of 100 ohms.; if another lamp be 
put in circuit, two circuits of 100 ohms, aro provided for the current, making the 
20 net total resistance to the current 50 ohms. 

Although tho resistance in each derived circuit remain unchanged, this effect is 
ordinarily opposite to tho effect produced by the addition of lamps when they aro 
connected in nn ordinary straight circuit, each one then adding to tho resistance of 
the circuit. The bringing into operation successively ol numbers of tho devices, 
25 nnd thereby making more paths or circuits for tho currents, does not appreciably 
lessen the pressure or diminish the cflect upon tho devices in uso, tho active force 
at the central station, vis., primo field of forco generators and motive power, 
remaining unchanged until tho net resistance of the devices in circuit exterior to 
the battery of machines is so diminished ns to approach in a degree the resistance 
30 of the baticry and main conductors, it being remembered that ns tho machines of 
a battery are connected in multiple arc the net internal resistance of a battery is 
as many times less than ouo as there aro machines in tho battery. 

To avoid any appreciable variations and insure uniformity it is essential that 
any lessening of pressure bo immediately indicated, in order tiiat just sufficient 
35 cncigy bo generated and sent out to keep up nil equal flow through tho circuit of 
each translating device, that is, that tho pressure be kept up uniform whether 
more or less translating devices be in circuit. 

This is obtnined by providing at tho central stations means for constantly 
indicating tho pressure and for regulating the production of appreciable variation 
40 he indicated at ench station test lights are arranged, so that an approximate 
visual test of tho cflect of pressure upon tho circuit of any translating dovicos in 
uso may bo shown. 

From what has boon said it is evident that as more or less translating devices 
arc brought into circuit the total resistance of tho circuit, or all tho circuits thereof, 
45 to tho flow of all the current generated varies. To indicate this clcctrodynnmo- 
meters, galvanometers, or electrometers me placed across tho main conductors at 
the central station, or by return wire nt any point in the circuit, with a zero mark 
placed to correspond with the deflection consequent upon tho maiutonanco of tho 
proper amount of pressure. 

•'0 It may bo ndvisablo (and I havo so dono) to place at the central station a series 
of standard “ Baniell’s " batteries, connected by a switch circuit to tho galvanometer 
w dynamo galvanometer, in order that they may bo frequently tested for any 
inaccuracy occurring from any causo whatever. By these moans any error wlnit- 
over therein is readily detected. „ . 

5 ° i’o correct variations in tho pressure various moans may be employed. .Mali 
supply genorntor may bo connected into tho circuit through a switch, and each 
series may bo likewise so connected, so that tbo current of ouo or more of a scries, 












Edison's Tm pts. in the Utilisation of Electricity for Light, Heat, and Power. 

or ono or more entire sorios, may bo out out or thrown into the circuit j or each 
mnchino may bo nrranged so 03 to bo disconnected from the prime motor, or when 
needed tho prime motor of an entire series may bo disconnected. _ 

The plan I prefer however is to arrnngo in connection with tho circuit of the 
battery feeding tho field of force magnets of tho primo field of force generator bofore 5 
referred to, a series of resistances so that tho energy of tho battery current may be 
varied this variation causing in turn a variation in current induced in primo field 
of force generator, and in all tho generators directly or indirectly controlled thereby. 
When a dynamo mnchino is used these resistances arc to bo used in same maimer 
in connection with the circuit including tho coils around tho field magnets. It 

For distributing the current thus generated and regulated at the central station, 

I prefer to use conductors within insulated pipes or tubing made water tight and 
buried in the earth, provision being made at suitablo intervals for house or side 
connections. , . , , 

While this plan is prefemblo for many reasons it is evident that conductors mny I; 
be earned in the air or over house tops. While only ono pair of conductors may be 
laid on each street, I prefer, especially whore streets are wide, to lay a pair of 
conductors along each side of tho street near tho curb. At proper intervals street 
lamps may be connected thereto by derived circuits. 

From mnin conductors on principal streets subsiduary main conductors nra laid 2( 
through side streets; from tho street conductors, wherever desired, derived circuits 
are led into tho houses, ono of tho conductors passing through a suitable meter, 
preferably ono which measures the amount of electricity passing through, ns set 
forth in my Patent, No. 422G, of October 23, 1878. _ . a . 

In the house each translating device is placed in a derived circuit, tho entire 
system of means for generation, conduction, and translation being ono great 
multiple arc system. Tho translating device in each house may be either for light 
or power, or both. For light, the electric lamp consisting of an incandescing 
material hermetically sealed in glass is preferred. . 

This lamp is made of high resistance in comparison with that of any electric el 
lamps which to my knowledge have been proposed. In lights heretofore proposed 
the endeavour seems to havo beon to lessen tho resistance of the carbon, none 
having been suggested of higher resistance than, say, 10 ohms., but I have discovered 
a very much higher resistance, say, 100 ohms., must bo used in order Unit a number 
may bo economically and successfully used in a system. _ 

The motor used Bliould bo so constructed that each with a constant flow or 
pressure of current will give the exact power required. . 

This requires that each motor should be wound with finer or coarser wire, and 
with more or less convolutions which determine tho maximum crtcct of tho motor. 

In addition, as the motors may be run with variable loads or amount of "’ orlc , 4 
perform, and as irregularity of speed would be a consequent thereof, it is preferable 
to provide each motor with a governor, which on cxcossive speed would operate to 
break the circuit of the motor or otherwiso control it. A preferable form ot 
governor, therefore, will form the subject matter of nu application for Patent to bo 
tiled by me. _ , , . ' 

A system arranged ns thus described provides for nil tho conditions precedent to 
an economical and reliable utilization of electricity as a lighting or motivo powoi 
agent. 

As within certain ascertainable limits tho greater tho horse power of nnengino ^ 
tho loss tho proportionate cost por home power, by consolidating at ono station 
prime motive force necessary to tho generation of a supply for many consume , 
great economy as to production occurs. ,.. 

As ordinarily proposed, each electric light requires its own regulator, wn 
usually is either thermostatic or magnetic, breaking the circuit or bringing 
resistances, in any case making a cumbrous lamp requiring delicate managem 
and constant attention. ■„ 

By regulating at the central station entirely I am enabled to uso n small sepa 


Edison's Impts. in the Utilization of Electricity for Light, Heat, and Power. 

lamp, which may be used with tho oxerciso of no more than ordinary care or 
attention. 

Tho distribution is so provided for that tampering therewith is guarded against, 
and that connections from tho mains to localities of translation aro readily mado. 
5 The means for measuring insures accurateness, mid in furnishing a basis for 
equitablo charges for tho amount used by ono particular consumer. 


SPECIFICATION in pursuanco of the conditions of the Letters Patent filed by 
tho said Thomas Alva Edison in the Great Seal Patent Office on the 11th 
August 1880. 

0 Thomas Alva Edison, of Menlo Park, in tho State of Now Jersey, United States 
of America. “Improvements in tiie Utilization of Electricity for Liairr, 
Heat, and Power, beixo an Improved System and Means for the Generation, 
Regulation, Distriuution, Measurement, and Translation of Electricity 
into Light, Heat, or Power." 

5 The object of this Invention is to so arrnngo a system for the generation supply, 
and consumption for either light or power, or both, of electricity that a l the 
operations connected therewith requiring special care, attention, or knowledge 
the art shall bo performed for many consumers at central stations, leaving tho 
consumer only the work of turning oft’ or on the supply, as may be desired; in 

10 other words, to so contrive means and methods that electricity may be suppl cd fo 
consumption in a manner analogous to tho system tor the supply of gas and water, 
without requiring any greater care or technics knowledge on the par of tho 
consumer than docs the uso of gas or water, in order that economy, reliability, and 
safety may be ensured. 

5 In carrying tho Invention inti 


In carrying tlTlnvention into effect a city town village or locality may fewm 
one district or if tho extent of territory makes it desirablo may bo dividod into 
several districts. In each district I provide a central station at which ^ grouped 
a suitable primo motor or several motors, dependent upon the amount tobesuppl.ed, 
generators or means for converting tho prime motivo for in order that a 

for determining tho amount of electricity generated “PP^f “ 

constant pressure of electricity (so to speak) may be Kept1- 1 ore 

arc any suitable engines, steam « , and one> oi own system of 

Er»r,c7.r”^ 

mass of metal in proportioo tothe mass o n eta poles 

tno generating coil. By tins extra lengcn, as o nxtensiona acting 

increases with their distance apart, tlioro is secured at P intensity or so 
upon tho coils in the revolving armature a much greutei mag t y, 







Edison’s Impta. in the Utilization of Electricity for Light, Ilcat, and Power. 

to speak a greater magneto motivo forco or pressure, causing consequently tlio 
generation of a greater amount of energy in tho coils operated on than would result 
from the use of shorter magnets, oven though tho saino moss of metal wero used 
therein. By this elongation of tho cores I am enabled to dispense with a number 
of layers of coils, as ono layer of wire is usually sufficient, whoroby tho resistance of 5 
tho machino is largely diminished. Tho largo mnss of theso magnet cores is 
magnetically saturated by a weak current passing around them. It takes this 
weak current a long timo to bring this mass of metal up to the point of practical 
maximum magnetic intensity, hue once brought to that point the wenk current 
readily keeps them thero, while with a shorter magnet a stronger current would 10 
more speedily magnetically saturate them; this stronger current would still bo 
required to keep them so saturated. 

If tho coils of the field of force magnets nnd tho generating coils wero included in 
one circuit, and all tho current generated was passed through the coils of tho Hold 
magnet, a very much greater amount of current than necessary for tho maintenance 15 
of a practical magnetic maximum in the field of force magnets would be passed around 
them, and the coils ucting as resistances to tho energy in excess of that required to 
magnetize the magnet to its practical maximum would cause a great waste of 
electric energy ; hence I prefer to keep the coils of the field of forco magnets nnd 
the generating coils separate, and that ono machine in caoli battery (which machine 20 
may bo termed tho battery field of forco generator) bo used to supply tho requisite 
energy to the field of force magnets of the other machines in such bnttory (which 
may be termed the supply generator). 

The coils of the field of force magnots are connected as a series or in multiple arc 
in one circuit, while the generating coils of the supply generators of each battery 25 
nre each and all connected in a multiple are to the main conductors (though for 
special purposes thoy may be connected as a series). 

This arrangement ensures great economy, ns the per cent, of tho entiro current 
generated in each battery nbsorbed in keeping up tho magnetic maximum in tho 
field of forco magnets when it is furnished by one special machine of the battery, the 30 
number given it to food being properly calculated, being less than when a portion 
of the current generated in each machine is absorbed in its own field of forco 
magnets. 

Where a single batteiy of machines is used it is preferablo, in view of what has 
been herein bcl'oro stated, for tho current to the coils of tho fiold of force magnets 35 
of tho battery generators bo supplied by a small galvanic battery, but if more 
than ono battery of machines bo used the field of force generators of nil tho batteries 
are led from ono or moro prime field of forco generators connected in a multiplo arc 
or in a series, tho field of forco magnets of tho prime fiold of force generator or 
generators used being kept mngnotically saturated by a weak galvanic battery 40 
current, as before set forth. For instance, a wenk galvanic current supplies tho 
field current necessary for one prime field of force generator, which in turn feeds 
tho field of force magnots of tho field of forco generators of ten batteries of twenty 
or thirty machines, the ultimnto effect in the generation of current depending upon 
(as ono important factor) tho tension of tho galvanic current sent through the field 45 
ot forco coils of tho primo field of forco generators. Tho prime field of force gene¬ 
rators may however be a-dynamo electric machino instead of a magneto machine, 
its field of force being kept up by tho current generated in the machino instead of 
by a galvanic current. 

At tho central stations all tho supply generating coils or batteries thoreof are 50 
connected .to conductors on tho multiple arc system, and from theso conductors 
at the station main conductors (which for convonionco may simply bo called tho 
mains), connected thereto also on tho multiple are system, leud in any and all 
desired directions for conveying tho enorgy to the points whero work either by 
translation into light or motivo power is to bo done. In order to givo a better ja 
understanding of the method of regulating what for convenience may bo called the 
pressure of the current through the entire system, I will hero state that all the 


spMiitMtiou. A.D. 1880.— N° 602. 7 

Edison’s Impta. in the Utilization of Electricity for Light, Heat, and Power. 

dovices for translation of electricity aro arranged on tho multiple arc system, each 
devico being in its own derived circuit, tho effect being in substance to give each a 
circuit from tho generating source independent of tho circuit of all tho other 
dovices. As a resultant it follows that tho greater tho number of translating 
5 devices brought into circuit the less the total resistance of tho circuit. For instance 
I prefer that my lamps shall eneh be of about ono hundred ohms, resistance, then 
if 011c lamp only be in circuit there is a resistance of ono hundred ohms.; if anothor 
lamp be put in circuit two circuits each of ono hundred ohms, are provided for tho 
current, making tho net total resistance to tho current fifty ohms. Although the 
10 resistance in each derived circuit remains unchanged, this effect is the opposito of 
the elioat produced by the addition of lamps when thoy are connected in an 
ordinnry straight circuit, each ono then adding to tho resistance of tho circuit. 

Tho bringing into operation successively or numbers of the devices, and thoroby 
making more paths or circuits for tho current, does not appreciably lessen the 
15 pressure or diminish the offect upon tho devices in use, tho active forco at the 
central station, viz., primo field of forco generators nnd motive power, remaining 
unchanged until tho net resistance of tho devices in circuit oxterior to tho battery 
of machines is so diminished os to nppronch in n degree tho resistance of tho battery 
and main conductors, it being remembered that as the machines of a battery aro 
20 connected in multiplo are the net internal resistance of a battery is as many times 
less than one machine os there aro machines in the battery. 

To avoid any appreciable variation and onsuro uniformity it is essential that any 
lessening of tho pressure bo immediately indicated, in order that just sufficient 
energy bo goneratod nnd sent out to keep up an equnl flow through the circuit of 
25 encli transmitting device; that is, that tho pressure bo kept up uniform whether 
more or less translating devices bo in circuit. 

This is attained by providing at tho central station means for constantly indicating 
the pressure and for regulating the production. If appreciable variation bo indicated 
at such station test lights aro arranged, so that an approximate visual test of tho 
30 effect of pressure upon the circuit of any translating devices in use may be shown. 
From wliat 1ms been said it is evident that as moro or less translating devices nre 
brought into circuit the total resistanco of the circuit, or all the-circuits thereof, to 
the flow of all tho current generated varies, 

To indicate this electro-dynamometers, galvanometers, or electrometers are placed 
35 across the main conductor at the contral station, or by return wire at any point in 
the circuit, with n zero mark plaeod to correspond with tho deflection consequent 
upon the maintenance of tho proper amount of pressure. It may be advisablo (and 
1 have so dono) to place at tho central station a series of standard Daniel batteries, 
connected by a switch circuit to the galvanometer or dynamo galvanomotor, in ordor 
40 Hint they may bo frequently tested for any inaccuracy occurring from any causo 
whatever. By theso means any error is readily detected. To correct variations in 
tho pressure various means may bo employed. Each supply generator may be 
connected into tho circuit through a switch, and each series may bo likewise so con¬ 
nected, so that the current of one or more of a series, or one or moro entiro series, 
45 may bo cut out or thrown into tho circuit; or eneh machine may be arranged so as 
to be disconnected from tho primo motor; or. when needed, tho primo motor of an 
entire series may bo disconnected. 

Tho plan I prefer however is to arrango in connection with tho circuit of the 
battery feeding the field of force magnets of the primo field of feree generator before 
60 referred to, a sorics of resistances so that tho energy of tho bnttory current may 
be varied, this variation causing in turn a variation in current induced in tho 
primo field of forco generator, and in all tho generators directly or indirectly 
controlled thereby; where a dynamo machine is used theso resistances aro 
to be used in the same manner in connection with tho circuit including tho 
55 c °ils around the fiold magnets. For distributing the current thu3 generated and 
regulated at the contral station, I prefer to use conductors within insulated pipes 
°r tubing niado water tight and buried beneath tho earth, provision being made at 





Edison’s I mpt*. in the Utilisation of Electricity for Light, Ileat, awl Power. 

suitablo intervals for liouso and side connections. While this plan is preferable 
for ninny reasons it is evident tlmt a conductor inny bo carried in tho air or over 
bouse tops. 

While only one pair of conductors may bo laid on oncli street, I prefer, especially 
where streets are wide, to lay a pair of conductors along each side of tho street near 5 
tho curb. At proper intervals stroot lamps may bo connected theroto by derived 
circuits. From the main conductors on principal stroels, subsidiary main conductors 
aro laid through side streets. From tho street conductors, wherever desired, derived 
circuits arc led into houses, ono of tho conductors passing through a suitable meter, 
preferably one which measures tho amount of electricity passing through. In tho 10 
house each translating device is placed in a derived circuit, tho entiro system of 
means for generation, conduction, and translation being ono great multiplo arc 
system. Tho translating device in each house may bo cither for light or power, or 
both. For light, the electric lamp consisting of nn incandescent material hermeti¬ 
cally sealed in glass is preferred. This lamp should bo of a high resistance in 15 
comparison with the resistance of any electric lamp which to my knowledge lias 
hitherto been proposed. Tho endeavour seems to linvo been to lessen tho resistance 
of the carbon, but I have discovered tlmt a very high resistance, say, one hundred 
ohms., must bo used in order that n number may be economically and successfully 
used in a system. 

The motor used should bo so constructed that each with a constant flow or 
pressure of current will give tho exact power required. This requires that each 
motor should bo wounil with finer or coarser wire, and with more or less convolutions 
which determine the maximum effect of the motor. 

In addition, as the motor may be run with variable loads or amounts of work to 2a 
perform, and as irregularity of speed would be a consequent thereof, it is preferable 
to provide each motor with a governor which, oil excessive speed, will operate to 
break the circuit of the motor or to otherwise control it. 

A system arranged ns thus described provides for all tho conditions precedent 
to an economical and reliable utilization of electricity ns a lighting or motive power 30 
agent. . 

Within certain ascertainable limits the greater the horse power of an engine tno 
less the proportional cost per horse power; so in my system by consolidating at one 
station the prime motive force necessary to tho generation of a supply for many 
consumers a grent economy is attained. _ " 

As ordinarily proposed, each electric light requires its own regulation, which usually 
is cither thermostatic or magnetic, breaking tho circuit or bringing in resistances, in 
any caso making a cumbrous lamp, requiring delicate management and frequent 
attention. By regulating at tho central station entirely I am enabled to use a 
small separate lamp which may bo managed with the exorcise of no moro than 40 
ordinary caro or attention. Tho distribution is so provided for that tampering 
therewith is guarded against, and that connections from tho mains to tho translating 
devices are readily made. Tho means for measuring ensure accuracy, and furnish 
a basis for equitable charges for the amount used by any particular consumer. ^ 

In the Drawings accompanying and forming part of this Specification an arrange- 4a 
meat of means is shown for carrying my Invention into effect, although it is to » 
particularly noted tlmt the Invention is not dependent upon tho specific '"j®”? 
and their arrangement described and shown, but that they inaybo varied ' vllll0 f 
departing from the spirit of my Invention. In those Drawings Fig. 1 isn plan o 
central station. ,K 

Fig. 2 is a modification of Fig. 1. 

„ 3 is a plan illustrating tho stroot mnins and house connections, with t rnns ‘ 
lnting devices properly introduced, _ 

„ 4 is a plan showing a locality divided into lour districts. In Fig. 1 t u 
batteries of generators o, c 1 , c“, are shown, which may bo increased or dunlinsii 
ns circumstances may demand. One generator c of each battery is used to genera 
tho current feeding tho field of forco magnets of tho machines in its battery, u 


Edison's Impts. in the Utilization of Electricity for Light, Heat, and Power. 


For actuating the rotary parts an engine D is used with each battery connecting 
by belt d to line of shafting E, from which belts e pass to ench generator. Tho 
5 coils of each mngnoto battery in which currents are generated are conneotod, as in 
c 1 and c-, in multiple arc to conductors 3, 3, 3, 3, which in turn aro connected in 
multiple arc to main conductors (i, 0, from which lead in multiple arc tho street 
conductors or mains 7, 7, or, ns is shown in part of battery e, each machine may bo 
directly connected in multiplo arc to the station conductor 0, (i. F is tho primo 
10 field of force generator supplying tho battery field of forco generators c, c, c, its 
circuit being shown in dotted linos 1, 1. Tho field of force magnets of F are 
magnetized by a current from the galvanic battery G, in whoso circuit is arranged 
the series of resistances H provided witli tho cut out K, by which more or less of 
the resistances are put in or out of the circuit feeding the field magnets of F. This 
IS arrangement forms a very effective and siinplo method of regulating the production 
of electric current or the pressure at the central station, for the current generated 
by F being dependent upon the intensity of tiie magnetization of its field of force 
magnets which in turn depends upon the current transmitted around the magnets 
by the battery G. As the resistance varies such current, it follows that by varying 
20 the resistance in the circuit of G tho current generated by F varies, which in turn 
varies the current generated in c, c, c, which in turn varies the current generated in 
the supply machines of the batteries, proportionate increase of current and rise of 
pressure in the latter following increase of current around the magnets of F, and 
vice versa. Ono or more test lamps T L are placed lit the central station in 
25 derived circuits to serve as a photometric test of the pressure in the line. For more 
accurately indicating variations in the pressure one or more electrometers, 
galvnnoineters, or electro dynamometers E D are placed in derived circuits witli 
scale marks indicating the deflection caused by the electric pressure so as to compare 
the snmo with the standard pressure to be maintained. By the proper use of these 
30 indicating devices aud tho regulating devices described, a uniform pressure may bo 
readily and easily maintained through all tho mains. It is preferable to connect 
nil circuits from the generating machines to the main conductors (i, G, through 
switches 1,1,1, so that nn entire battery or any portion thereof may be thrown in 
or out of circuit ns the demand upon the station may indicate. It is to be noted also 
35 tlmt tho belt to tho pulley of ench machine is to be so arranged by any well known 
plans that it may be disconnected from the motor when desired, and in this mnnnor 
tho number of machines in operation may be controlled, and the effective force of 
each machine while in operation is regulated by the resistance in the circuit G. 


nil circuits from the generating machines to the main conductors G, G, through 
switches 1,1,1, so that nn entire battery or any portion thereof may be thrown in 
or out of circuit ns the demand upon tho station may indicate. It is to be noted also 
35 tlmt tho belt to tho pulley of ench machine is to be so arranged by any well known 
plans that it may be disconnected from the motor when desired, and in this mnnnor 
tho number of machines in operation may be controlled, and the effective force of 
each machine while in operation is regulated by the resistance in the circuit G. 
The engine may be of any desired pnttorn or power, the number of machines in any 
40 ono battery being limited by the power of the engine. 

In Fig. 2 c, e, c, c, are the generators for the iickl of force magnets in batteries 
not shown, andV is’ the field of force generator of a battery of which three supply 
generators c\ c", c 1 , are shown connected to station conductors G, G, ns before 
explained. ... 

45 Tho prime field of force generator F 1 is in this case a dynnmo-electric mnclune 
instead of a magneto electric machine, as shown in Fig. 1, nil its coils being included 
in ono circuit 878, which passes around the field of force magnets of tho battery 
generators c, c, c, c, c 1 . The same principle of regulation is used howovor, the 
resistance li and cut out 1C therefore being arranged in connection witli tho circuit 
50 through F> so ns to cause variation in the tension of tho current therein, ns and 
with tho result before oxplainod. In this Figure there is shown what may bo used 
also in connection with the plan shown in Fig. 1, vis., means of testing the eleotro- 
dynamometer E D or other Indicating instrument used, hrom a standard Daniel s 
Battery, DBa circuit tc may be formed through ED by means of the switch L 
55 when moved to the position shown by clotted lines, so that the correctness of ED 
nml anv inaccuracies winch might ariso bo guarded 






10 A.D. 1880.—N° 602. spccifau*. 

Edison’a Impta. in the Utilization of Electricity for Light, Heat, and Power. 

against; usually tins switch L remains as shown in full lines, and ED is in a 
branch botween tho main conductors C, C. 

The main conductors 7, 7, Fig. 3, aro to bo connected with tho corresponding 
wires at central stations (soo Fig. 1), and lead down cnch sido of tho street M S. 
Tho conductors 7, 7, also branch ofT into intersecting streots IS. Tho small 3 
circles o in this Figuro indicato electric lamps. For street lighting they aro placed 
ns shown in derived circuits from tho street mains. From tho mains derived 
circuits 0, 0, lead into houses, in which aro placed at suitable spots tho meters M, 
through which one of tho house conductors passes, and by which tho amount of 
electricity supplied to tho houso is accurately determined. Upon theso house 10 
circuits are arranged lamps o, on tho multiple arc system, in such number, position, 
and grouping, ns may bo desired. In theso circuits I also propose to introduce 
electro-motors E M, wherever desired for furnishing light motive power. From tho 
motor a belt i leads to a lino of shafting h and pulleys a, a, for any needed dis¬ 
tribution of tbe power, or tho belt i may pass directly to a sowing or other 15 
machine, a separnto motor being used for cnch power drivon machine. 

Whero motors aro desired each preferably should bo mado of a power propor¬ 
tionate to the maximum work to bo done. AVhilo tho electrical tension in each 
machine is rogulated at tho central station, yot if tho maximum load or work bo 
diminished at any particular motor its speed would necessarily bo increased; it SO 
also might be desired at times to diminish tho normal speed of the motor. In 
order, therefore, that somo determinate speed may bo maintained irrespective of 
load or work, each motor should bo furnished with a governor to rcgulute the 
electric circuit and tho speed. 

In Fig. 4 is shown a locality divided into four supply districts; each is provided 25 
with its own central station marked OS', CS 2 , OS :1 , and CS 1 . From cnch station 
the mains 7, 7, lead out, ns before described. At convenient points, howover, say 
1? P, connections between the mains of tho stations may be made, ns shown in 
dotted lines, the effect ttien being to merge the entire locality into one large district 
with four supply stations, tbe pressure through all being uniform, and each station 30 
doing its own quota toward maintaining the uniform pressure. The use of four 
stations and districts in this diagram is arbitrary, and for illustration only, ns the 
number actually employed in any ono locality depends upon the area of the district 
and tho number of lights to bo maintained. 

What 1 claim as my Invention is,— 35 

First. A system for tho generation and application of electricity consisting in 
tho combination of means at a central station for generating the electricity and 
for indicating and regulating its pressure, means for distributing tho electricity, 
and devices for translating it into light or motivo power, substantially as set 
forth. t W 

Socond. A system for tho generation and application of electricity consisting in 
a combination of means at a central station for generating tho electricity, and for 
indicating and regulating its piossure, means for distribution, menns for translating, 
and means for measuring tho amount used by each consumer, substantially asset 
forth. . 

Third. Tho method of regulating tho electro motivo forco or pressure in the main 
conductors by regulating the strength of the field of forco magnoU of the main 
magneto electric machines, so that variation of pressure upon tho connection or 
disconnection of translating devices may bo prevented, substantially ns sot forth. 

Fourth. Tho method of regulating tho amount of offset at the translating devices 6* 
by regulating tho field of force current of tho generators, substantially as set 
forth. 

Fifth. Tho method of regulating tho generative capacity of ono or a battory of 
magneto cloetrio or dynamo electric machines by regulating tho current passing 
through tho field of forco magnets, substantially as set forth. , 9 

Sixth. The method of regulating tho generative capacity of one or a battery of 


s^uauion. A.D. 1880.—N“ 602. 11 

Edison's lmpts, in the Utilization of Electri city for Light, Heat, and Power. 

magnoto olectrio or dynamo electric machines by varying tho resistance of tho 
eircuit passing around tho field of forco magnets, substantially as set forth. 

Sevonth. Tho method of operating a battory of magnoto olectrie machines by 
using tho entire current of ono machine of tho battory to supply tho field of forco 
5 current of tho remainder, and throwing tho entire current of tho latter into a circuit 
for use, substantially as set forth. 

Eighth. The combination .with ono electrical circuit of a number of separnto 
translating devices, substantially as sot forth. 

Ninth. Tho combination with ono main electrical circuit of a number of separate 
10 translating devices arranged therein upon tho multiple arc systom, substantially as 
set forth. 

Tenth. Tho combination with n number of translating devices of ono regulator 
placed at a central station and regulating all the said devices, substantially as set 
forth. 

15 Elovcnth. The combination with ono or a battory of gonorators and a number of 
translating devices of means for constantly indicating tho oleetrie pressure upon tho 
translating devices, substantially as sot forth. 

Twelfth. Tho combination of a number of gonorators and a number of trans¬ 
lating doviccs, all arranged upon derived circuits or multiple arcs, substantially as 
20 described. 

Thirteenth. Tho combination with moans for constautly indicating tho electric 
pressure of a battery for testing tho indicating means, substantially as described. 

In witness wlioreof, I, tho said Thomns Alva Edison, have hereunto set my 
linnd and seal, this 29 day of Juue, A.D. 1880. 

25 THOMAS AI/VA EDISON. (l.s.) 

Witnesses, 

S. L. Griffin. 

Frank MHjAuani.iN. 













































A.D. 1880, MiApiul. N° 1385. 


Electric Machines and Motors. 


LETTERS PATENT to Thomas Alva Edison, of Menlo Park, in tlm State of Now 
Jersey, United States of America, for an Invention of “Improvements in 
Dynamo or Maoneto Ei.ectiuc Machines and Electric Motors." 


PROVISIONAL SPECIFICATION left by tlio said Thomas Alva Edison at the 
Ollice of tho Commissioners of Patents on the 5th April 18S0. 

Thomas Alva Edison, of Menlo Park, in tho State of New Jersey, United States] 
of America. “Improvements in Dynamo or Maoneto Electric Machines 
5 and Electric Motors.’ 


A portion of my Invention rolates to tho rotating armatures, the arrangement of 
tho commutator brushes or contacts, and tho shaft of the rotating armature and 
commutator, which are applicable to both dynamo or magnoto electric machines 
and to eloctric motors. 

10 In rotating armatures mado of a solid mass of metal, or of sovernllarge rings of 
metal, currents are induced in the armature itself,' which circulate from points of 
greatest to thoso of lowest potential. 

To such currents is largely duo tho lioating of tho armature so often presont as 
an injurious element in Buch armatures. 

15 To remedy this I construct an nrmaturo of a number of vory thin discs or rings 
secured together upon a proper shaft or base, and slightly insulated from each other. 
I havo found that very good rosults are attained by using discs or rings, ono thirty 
second to ono sixty fourth of an inch thiok, separated from each other by sheets of 
tissuo paper. As currents induced in tho rotating armature havo very small electro 
20 motive force, the insulation of tho tissue paper and the thinness of tho plates prevent 
almost, if not quite, entirely tho circulation of induced ourrents and tho hoating 
attendant thereon. By this the effective capacity of tho mnehmo for conversion is 
very largely increased, for whilo the heating at onomoinontis not largo tho covonng 
of tho armature prevents radiation, and the accumulation of heat proceeds faster 
25 than its dissipation, and the armature becomes an accumulating receiver of heat 
until the capacity of tho mnehino for conversion is much impaired by limitation of 
exterior energy due to this heating, all of which is obviated by this uso of 
exceedingly thin plates or discs. In this connection, ns tho word thin is a relativo 
ono, it is well to state that the plates should bo at most not more than an eight of 
[Price Gtl.’l 










2 A.D. 1880.—N° 1385. 

Edison's Improvements in Electric Machines and Motors. 


nn inch thick, mid preferably very imicli tliiimcr mid insulalod from each other in 
order to attain tlieso clients. 

Commutator springs or brushes have always been arranged at right nii-dos to the 
axis of tho commutator. 

With such there hns usually lioen a large amount of "spark " on the face of the 5 
commutator indicating a loss of electric energy by its conversion at a point where 
conversion was not only unneoded, but injurious, causing a rapid destruction of the 
commutator apparatus. I find that this can lie largely and usually entirely avoided 
by arranging tho commutator springs or brushes so that their axial line is at an 
angle other than a right angle with tho axis of tho commutators, or in other words, 10 
that tho brushes or springs bear obliquely upon the face of tho commutator. 

In practice I liavo found that it is bettor that tho brushes or springs stand at nn 
angle of about 30° to tho axis of tho commutator. 

As ordinarily arranged tho brushes or springs travel over tho face of tho com¬ 
mutator in a uniform track speedily wearing a groovo therein, rendering the face of 15 
the commutator uneven. 

To remedy this, insuring even wear over the whole surfaco of the commutator, 
and also to iusure even wear and polishing of the surfaco of tho revolving armature, 

I nrrango the shaft of tho commutator and its bearings so that tho shnft may linve 
a longitudinal movement in tho bearings. Upon tho outer end of the shaft a disc 20 
is fixed forming a circular armature to an electro magnet suitably attached to the 
frame of the machino. When this magnet is charged, attracting the armature, the 
shaft is moved in ono direction to its limit of motion, a spring serving to forco it to 
the other limit when the magnet is inactive. 

If an iron pulley be used upon tho shaft of tho armnlure and commutator and 25 
placed near tho polar extension of tho field magnots the spring may be dispensed 
with, tho magnet for moving tho shaft being placed to move the shaft in one 
direction, the attraction between the machino mngnots and the pulley serving to 
movo the shaft in the other direction. Attached to any rotating part of the 
apparatus is a disc, a portion of whose periphery is of insulating material, the 3U 
remainder being a conductor, or tho disc may have several alternating conducting 
and non-conducting portions. Upon tho disc bears a contact spring, the disc and 
spring being interposed in a circuit loading from a battery or other source of 
electricity to the magnet last spoken of, or tho current therefor through a shunt 
may be a portion of the machine itself, ono rotating disc and spring may be arranged 35 
to control tho circuit of tho shaft moving magnets of a largo number of machines or 
motors. " c 

In providing electro motors for any given work it is desirable that any ono 
motor should bo constructed to givo tho maximum power required with a certain 
definite curront. 40 

As is the caso with all motors, howover, it may bo desired to use tho motor for 
less than its maximum capacity, that is to run it with a variable load or amount 
of work to bo performed, it is preforablo that it should bo provided with a 
governor to^correct any fluctuations in speed consequent upon such variation in 

To accomplish this I plnco on the main shaft, or I gear to it either directly or 
by belting, a centrifugal govornor which lifts upon too great speed, an adjustable 
circuit lover controlling by uitlior making or breaking directly or indirectly the 
circuit to tho motor; this lever may control directly the circuit to tho motor 
passing through it, or it may control indirectly by controlling a local buttery oU 
circuit to a magnet, whoso armature lover operates n circuit breaker placed i« 
motor circuit. In order to prevent too sudden fluctuations upon tho breakage o 
circuit, and to maintain regularity while the currant is on, the main shaft « 
provided with a heavy fly or balance wheel, whoso momontum prevents irregularities 
and causes gradual slowing down when tho circuit is broken. As tho circuit a 
controlling lever of tho governor completes tho circuit through an adjustable stoU 
tho joint effects of tho governor and fly wlioel are that the mnehino is capable o 


A.D. 1880.—N° 1385. 


Edison's Improvements in Electric Machines and Motors. 

the finest adjustment, breaking and completing tho circuit upon tho least 
variation from a determined desired speed acting exactly', so to speak, as an 
automatic cut oil' in steam engines, preventing unnecessary consumption of 

5 The breaking of tho main circuit occasions a largo spark at tho breaking point, 
which is more destructive ns a unit than it would be if divided into several sparks, 
hence 1 break tho mam circuit when breakago is necessary at several points 
simultaneously, in order to divide the spark and lesson its total injurious effect. 

I accomplish tins by fixing upon nn insulating base several contact springs, tho 
10 free ends of which rest each respectively upon proper contact posts, and project 
slightly beyond tho smuc. Tho circuit is led to ono post, passes to its spring 
whence it passes by a wire to tho next post into its spring by wire to next post, 
and so on through tho series of springs and posts. Either tho circuit controlling 
lever or the armature lever, as either is used for the purpose as before explained, is 
15 broadened at tho end, so as to take under the extreme free ends of all the circuit 
springs, and upon desired movement lift them from their posts, breaking tho main 
circuits at a number of points. 

In using electric motors, especially for actuating light machinery’, it is very 
desirable that the rate of speed of the actuated machino bo under control of the 
20 operator, and that tho means of control lie simple, effectual, and easy of application. 

Hitherto this 1ms been attempted only through controlling the eleetrie circuit to 
the motor, breaking or closing it in whole or in part. 

1 propose to control the speed by tho application of a brake to tho main driven 
wheel without reference to the current. A brake is so pivoted as to be capable of 
25 hearing upon the wheel, but kept therefrom normally by’ a spring. 

Attached to the brake is a lever which in turn is attached to a treadle, by 
means of which any desired pressure may be applied, though it is evident that 
the brake lever may be arranged to bo operated by hand instead of through tho 
medium of n treadle. 

30 So far as I am aware electric motors have alwnys been connected direct to tho 
actuated machine, so that tho rate of speed of tho actuated machino and of the 
motor were the same. It is often desirable that tho actuated machino be drivon 
at a less or at a greater rate of speed than the motor. To effect this I interpose 
between the two differential gearing, that is, gearing which may bo cogged wheels, 
33 pinion wheels, friction gearing, belts and pulleys, or equivalents of different diameter, 
arranging them to produce the desired differential speed. 














A.D. 1880.—N° 1385. 


Edition's Improvements in Electric Machines and Motors. 


SPECIFICATION in pursuance of tho conditions of tho Letters Patent filed by 
the suid Thomas Alva Edison in the Great Seal Patent Office on the 5th 
October 1880. 

Thomas Alva Edison, of Menlo Park, in tho Stale of New Jorsoy, United States 
of America. “ Imphovements in Dynamo on Maonkto-electiuc Machines 5 
and Electiuc Morons.” 

A portion of iny Invention relates to the rotating armature, the arrangement of tho 
commutator brushes or contacts and tho shaft of tho rotating armature and com¬ 
mutator, which aro npplicablo to both dynamo or inngneto electric machines and to 
electric motors. 10 

In rotating armatures nrndo of a solid mass of metal, or of several large rings of 
mctnl, currents are induced in the armature itself which circulate from points of 
grontest to those of lowest potential. 

To such currents is largely due the heating of the armature so often present as 
an injurious element in such armatures. 15 

To remedy this 1 construct nn armature of a number of very thin disks or rings 
secured together upon a proper shaft or base, nud slightly insulated from cncli 
other. 1 have found that very good results aro attained by using disks or rings 
one thirty second to one sixty fourth of an inch thick, separated from each other 
by sheets of tissue paper. As currents induced in tho rotating armature have very 20 
small electro-motive force, the insulation of the tissue paper and the thinness of 
the plates prevent almost, if not quite, entirely the circulation of induced currents 
and tho heating attendant thereon. I iy this the effective capacity of the inacliino 
for conversion is very largely increased, lor while tiro heating at one moment is not 
large, the covering of tho armature prevents radiation, and tho accumulation of 05 
heat proceeds faster than its dissipation, and tho armature becomes an accumulating 
receiver of heat until the capacity of the machine for conversion is much impaired by 
limitation of exterior energy duo to this heating, all of which is obviated by this 
use of exceedingly thin plutes or disks. I11 this connection, as tho word “ thin ” is a 
relative one, it is well to state that the plutes should ho at most not more than an 30 
eighth of an inch thick, and preferably very much thinner and insulated from each 
other in order to attain these effects. 

Commutator springs or brushes have always been arranged at right nngles to the 
axis ol the commutator. With such there lum usually been a largo amount of 
“spark” on the lace of the commutator, indicating a loss of electric energy by its 35 
conversion at a point where conversion was not oidy unneeded but injurious, causing 
a rapid destruction of the commutator apparatus. 

I lind that this can be largely, and usually entirely, avoided by arranging tho 
commutator springs or brushes so that their axial lino is at nu angle other than a 
right angle with the axis ol' tho commutators, or in other words, that tho brashes or 40 
springs bear obliquely upon tho liico of tho commutator. 

in practico I have found that it is hotter that the brushes or springs stand at an 
angle of ubout 80° to tho uxis of the commutator. As ordinarily arranged tho 
brushes or springs travel over the face of tho commutator in an uniform track, 
speedily wearing a groove therein, rendering tho face of the commutator uneven. 45 
io remedy this, ensuring oven wear over tho whole surface of the commutator, 
and also to ensure oven wear and polishing of the surface of tho revolving armature, 

I arrange the shaft of tho commutator and its bearings so that the shaft may havo 
a longitudinal movement in tho bearings. Upon tho outer end of tho shaft a disk 
is tixed, forming a circular armature to an electro magnet suitably attached to tho 50 

lramo ol the machine. Whuu ibis magnet is charged, attracting the armaturo, the 

Shalt is moved in one direction to its limit of motion, a spring sorving to <“ rce ,l 
to the other limit when tho rnagnot is inactive. 


_ BdMm's Improvements in Electric Machines and M otors.. 

If an iron pulley bo used upon the shaft of tho armaturo and commutator, and 
placed near tho polar extension of the field magnots, tho spring may bo dispensed 
with, the magnet for moving tho shaft being placed to move the shaft in one 
direction, tho attraction between tho machine magnots and tho pulley serving to 
5 inovo tho shaft 111 tho other direction. Attached to any rotating part of tho 
apparatus is a disk, a portion of whoso periphery is of insulating material, tho 
remainder boing a conductor; or tho disk may have sovoral alternating conduction 
and non-conducting portions. Upon tho disk bears a contact spring, the disk and 
spring boing interposed 111 a circuit lending from a battery or other source of 
10 electricity to tho magnet last spoken of, or the current therefor through a shunt 
may bo a portion of the machine itself. One rotating disk and spring may bo 
arranged to control tho circuit of tho shaft moving magnets of a largo number of 
machines or motors. 

In providing electro motors for any given work it is desirable [that any ono 
15 motor should bo constructed to givo tho maximum power required with a certain 
definito current. As is tho case with all motors, however, it may bo desired to uso 
the motor for less than its maximum capacity, that is, to run it with a varinblo 
load or amount of work to he performed; it is preferable that it should be provided 
with a governor to correct any fluctuations in speed consequent upon such variation 
M in load or work. To accomplish this I place on the main shaft, or I gear to it, 
either directly or by belting, n centrifugal governor which lifts upon too grent 
speed, an adjustable circuit lever, controling by either making or breaking, directly 
or indirectly, the circuit to tho motor. This lever may control directly the circuit 
to the motor passing through it, or it may control indirectly, by controling a local 
battery circuit to a magnet whose armnture lever operates a circuit breaker placed 
in tjm motor circuit. In order to prevent too sudden fluctuation upon the breakage 
of Circuit, and to maintain regularity while the currcut is 011, tho main shaft is 
provided with a heavy fly or balance wheel whose momentum prevents irregu¬ 
larities, and causes gradual slowing down when tho circuit is broken. As tho 
ji) circuit controling lever of tho governor completes tho circuit through an adjustable 
slop, the joint effects of the governor and fly-wheel are that tho inacliino is capable 
of the finest adjustment, breaking and completing tho circuit upon tho "least 
variation from n determined desired speed, acting exactly, so to speak, as an 
automatic cut-off in steam engines, proventing unnecessary consumption of 

The breaking of the mnin circuit occasions a Inrgo spark at the breaking point, 
which is more destructive as a unit than it would bo if divided into several sparks, 
hence I break tho main circuit, when breakngo is necessary, at several points 
Mnultancously in order to divide the spark and lessen its total injurious effect. 

10 1 accomplish this by fixing upon nu insulating base several contact springs, tho 
Irce ends of which rest each respectively upon proper contact posts, und project 
slightly beyond the same. Tho circuit is led to ono post, passes to its spring, 
''hence it passes by a wire to the next post and its spring, and by wire to tho 
next post, and so on through the scries of springs and posts. Eithor tho circuit 
” C0| droling Jovcr or the armature lever, ns eithor is used for tho purposo as before 
c Mimincd, is broadened at the end so ns to take under tho extromo free ends of 
r the circuit springs, and upon desired movement lift them from their posts, 
rcakmg the main circuit at a number of points. 

, ." us “ig electro motors, especially for actuating light machinery, it is vory 
° “ Mat the rate of speed of tho actuated inacliino bo liudor control of tho 

^perator, and that tho means of control bo simplo, effectual, and easy of 

jl “'Mcrto this has been attempted only through controling tho electric circuit to 
55 «neon t0r ’ ^ ,oa * iin K or closing it in whole or in part. I propose to control the 
to H ^ the application of a brako to tho main drivou wheel without reference 
but it cun ’ unt> A brake is so pivoted us to bu capable ot bearing upon tho wheel, 

kept therefrom normully by a spring. Attached to tho brako is a lever which 










5 A.D. 1880.—N° 1385. a**** 

Edison'8 Improvements in Electric Machines anil Motors. 

n turn iff attached to n treadle, by menus of which nny desired pressure may be 
applied, though it is evident that-tho bmko lever may be arranged to bo operated 
jy hand instead of through the medium of a treadle. 

So far as I am aware electric motors have always been connected direct to the 
lotuated machine, so that tho rate of speed of the actuated machine and uf the 
uotor wero the same. It is often desirable that the actuated mnehino be driven 
it a less or at a greater rate of speed than the motor. To effect this I interpose 
jutwcon the two differential gearing, that is, gearing which may be cogged wheels, 
union wheels, Inction gearing, belts, and pulleys, etc., of different diameters, 
irrnnging them to produce tho desired differentiation of speed. 

Kofemng now to the Drawings for a more particular description, 

Fig. 1 is a detailed view of several parts detached from Fig. 2. 

„ 2 is an isometric view of a machine embodying a portion of tli i | 
orming the Invention herein claimed. 

Fig. 3 is a plan view. 

„ -I, an end view, and 

„ !> a side view of a motor and actuated machine showing nnother portion uf 

lie Invention herein claimed. 

a is a rotating armature which revolves between polar extensions of magnets not 
iccessnry to bo shown. This armature is composed of a number of thin plates, 
■ings, or disks secured upon the shaft b, thin pieces of insulating material, preferably 
issue, alternating with the plates, rings, or disks, and separating cncli of them from 
ill the others. The black lines at <i' show the metallic plates, the intermediate white 
hies representing the insulating material. The plates, disks, or rings should not 
ixeced one eighth of an inch in thickness, while the best results are obtained when 
.lie thickness is from one sixty fourth to one thirty second of an inch, d, d, aro the 
lommutator brushes or springs resting against the commutator d -, tin i biuslii", 
ire secured in stands d l capable of horizontal and vertical adjustment, ns shown. 
Vs more clearly shown in Fig. 1 the springs or brushes are placed obliquely to the 
ixis of the commutator, preferably at an angle of about 30°. The shaft b of the 
revolving armature and of the commutator is supported in boxes c, anil is iinangul 
,o have a longitudinal movement therein. Upon the end of the shaft b is fixed a 
lisk/, which forms tho armature for a magnet m ; whose poles p, p, me i slnukd, 
is shown, to exert their influence upon /. Through the magnet passes an electrical 
circuit y, y, in which is placed a circuit interrupter, consisting of a spring it whose 
roe end bears upon a hub or disk t, whose surface is composed of alternate con¬ 
ducting and nonconducting material, one or a series of alternations being used. 
While the spring u bears on a conducting portion of t tho circuit through m is 
jompleto, and tho poles p, p, attract /, pulling tho shaft b to its limit of movement 
in one direction. When tho circuit is broken a spring a forces the shaft to its limit 
n tho opposite direction. The hub or disk t may bo attached to nny rotating part 
jf a lnachine, or it may be driven by an independent motor. If it bo so geared 
that its rate of speed is different from that of b, tho movements of b will not occur 
it tho same relative time in consecutive rotations, and tho wear of the commutator 
ivill be evenly distributed over its wholo face, and the rotating armature will also 
ue evenly worn and polished. I prefer that mica bo used ns tho insulating material 
between the metal bars or strips of tho commutator. One circuit breaker «, t, may 
control the circuit for a number or battury of generators or motors; or a series ol 
them may bo arranged upon ono shaft, each controling the circuit to a generator or 
to u motor, and arranged to operate iu succession. , 

As before stated if an iron pulley bo used upon the shaft b it may be so arranS^ 
that the attraction between it and tho not shown magnets of tho mnehino will u,ov 
the shaft in ono direction, tho attraction between / and p, p, moving it in the °“ 1C ' 
in which enso the spring a is dispensed with. _ .. , 

<J is a centrifugal governor connected to tho shaft b by a belt q ; it is 
however that this governor may bo placed on the shaft, or may bo geared direcuy 
thereto. Tho sliding tubo «/ of tho governor, raised or lowered by tho action 


Edison’s Improvements in Electric Machines and Motors. 

tho governor balls, carries a sliouldor h taking under a pivoted lever Id, whose fruo 
end normally rests upon an adjustable stop i. The circuit x, of a small battery 
1,1! passes through the lever Id and stop i. This circuit x, x, also passes through 
an electro magnet I 1 whoso armature lever n is pivoted in suitable standards 1, 2 ; 

5 the free end of this lever n is widened out into a plato which takes under the free 
ends of a scries of circuit springs, in this case four in number o', o-, n ", o', which 
number however may he greater or less, as desired. These springs aro attached to 
an insulating supportand are arranged when not lifted by n to rest upon contact 
posts r\ i~, r\r'. The motor circuit AI C passes to the spring o' and post r 1 , then 
10 by wire to spring o' and post r 2 , and so through the series. The lover Id and part i 
are adjusted so that they shall remain in contact wlionever a desired predetermined 
speed is not exceeded, hut that Id shall bo lifted from i when such speed is exceeded. 
In this latter ovent tho circuit x, x, is broken between Id and i, the magnet l l is 
discharged, the armature lever n is raised by tho force of its spring lifting the 
15 springs o', o 2 , etc., from their posts, and breaking at each tho motor circuit me. 
fly this means a motor may bo kept in action with a steady speed, and tho 
destructive effects of ono largo main circuit spark lessened veiy materially by 
dividing into several minor sparks, or by increasing tho numbor of springs and 
contact posts for breaking tho main circuit nny sonsiblo spark effect may bo 
20 entirely obviated. 

If desired the battery L B, circuit x, x, and magnet I 1 may bo dispensed with, 
anil the springs o', o', o’, o', etc., be operated by the lever Id. 

Further, several magnets l' mid armatures might he used, one boing assigned for 
each spring, or for each division of two or more springs of the entire number used. 
25 In addition upon the shaft b is mounted a heavy lly or balance wheel F, W, whoso 
momentum serves to avoid too sudden fluctuations ill speed upon breaking the 
circuit. 

In Figures 3, 4, and 5 a 1 is nny suitable electro motor in which is the rotating 
armnlure, on whoso shaft is a commutator cf, upon which press the springs or 
30 brushes it, d, for completing tho circuit from tho conductors 1, 2, to the motor. 
Upon tho shaft is tho pulley Id secured thereto by friction, the friction being so 
adjusted that the pulley and shaft shall bu held and move together when only tho 
resistance of tho actuated machine is to bo overcome, but that whenever a greater 
resistance is offered tho friction shall be overcome and the shaft rotato within tho 
35 pulley without rotating it. From the pulley b' a licit id leads to tho large fly 
pulley id secured to the frnmo of tho actuated machine. Upon tho shaft of id is 
the pulley id, from which a belt id transmits tho motion to tho actuated machiuo. 
Upon tho undersido of tho table c 1 , or to any convenient part of tho frame, is 
pivoted a brake e 5 , adapted to be brought to bear upon the pulley id, but hold 
40 normally from so doing by a spring x. To tho brake 0 s is pivoted tho rod e", which 
passes down and is connected with a treadle c 7 underneath tho table. 

Through this trcadlo then any desired pressure may bo put upon tho periphery 
of the wheel b", regulating its speed, tho current to tho motor remaining unaffoctod 
""d its rotation continued. To tho switch s' is attached a rod id which passes to 
45 the front of the mnehino within cosy reach of tho operator. This switch is used to 
complete or break tho circuit to the motor. 

The switch may if desired bo placed upon tho frame or table ot tho actuated 

. The form of the brake used may lie varied; for instance, it may bo a belt 
5(1 tightener, tho bolt 6 s boing normally lonso and tho brake arranged to tighten it so 
that it will take upon the pulleys and transmit motion from ono to the other. 

'Vhal I claim is,— 

hirst. A rotating armature, composed of thin metal plates, disks, or rings, ns 
described, with alternating interposed insulating material, secured together upon a 
65 Shalt or hub, substantially ns sot forth. 

Second. The combination with a commutator of contact brushes or springs, 
arranged at nn angle to tho axis of the commutator, substantially as set forth. 














8 A.D. 1880.—N° 1385. < P o M » w , w 

_ Edison'a Improvements in Electric Machines and Motor*. 

Third. Tho combination with tho shaft of a commutator or rotating armature or 
both, adapted to lmvo a reciprocating movoment in its supporting iournals’ of 
means for giving such motion, substantially as sot forth. 

Fourth. The combination with a rotating slmft of a commutator or armature, or 
both, of an arninture, a mngnet, and a circuit controling device for givin** a rcciiiro- 5 
eating motion to the slmft, substantially as set forth. ° * 

Fifth. Tho combination with a revolving armaturo of a governor receiving 
motion therofrom, and adapted to control tho main circuit, substantially as set 
forth. 1 

Sixth. Tho combination with a revolving armature of a fly or balance wheel 10 
substantially as sot forth. 

Seventh. Tho combination with tho mnin circuit of a circuit breaker, adapted to 
break or closo tho main circuit at several points simultaneously, as set forth. 

Eighth The combination with an electro motor of a brako applied to tho main 
driven wheel, substantially as set forth. X5 

1 coml)ination wit 1 ' an electro motor of a friction pulley on tho rotating 

Shalt of the motor and a brako applied to tho mnin drivon whool and adapted to 
control its speed, substantially as set forth. 

Tenth. The combination with an electro motor of a mochnnical brako adapted 
to control the speed of the actuated machine, substantially as set forth. 20 

In witness whereof, I, tho said Tliomns Alva Edison, have hereunto set my 
hand and seal, this Seventeenth day of September, A.D. 1880. 


Witnesses, 

CnA". H. S.MiTn, 14' 
Geo. T. Pinckney, „ 


THOMAS ALVA EDISON. (l.s.) 























A.D. 1880, 16 th September. N° 3765. 


Eleotrio Lamps, S 


LETTERS PATENT to Edward Griffith Brewer, of 33, Chancery Lane, in the 
County of Middlesex, for an Invention of “ Improvements in Electric 
Lamps, and in Carbons or Incandescing Conductors therefor, and in 
Means for and Methods of Manufacturing the same.” A communication 
from abroad by Thomas Alva Edison, of Menlo Park, in tho State of New 
Jorsoy, United States of America. 


PROVISIONAL SPECIFICATION loft by the said Edward Griffith Brewer at 
tho Office of the Commissioners of Patents on tho lGtli September 1880. 

Edward Griffith Brewer, of 33, Chancory Lane.in tho County of Middlesex. 
“ Improvements in Electric Lamps, and in Carbons or Incandescing 
5 Conductors therefor, and in Means for and Methods of Manufacturing 
tiie same." (A communication from abroad by Thomas Alva Edison, of Menlo 
Park, in tho State of Now Jorsoy, United States of America.) 

As is now generally known, the inventor prefers to use in his system of olectrio 
lighting an electric lamp consisting essentially of an incandescing conductor sealed 

to - ,1«, oF aketri. lam ^a, tb. 
practice, so far as tho invontor knows, has been to make them of 'asi low re ?' stl ““ 
as possiblo, a porous carbon having been used which was dipped or .... 
cabonizablo liquid until its pores woro filled and then subjected to recarbon hon, 
W which process was repeated until tho pores of the original carbon were filled with 

^By" this process tho resistance of the carbon is lessoned, while its liability to 
disintegration undor high heat is increased. , 

„„ Such carbons are unfit for use in electric lamps giving light by mcandescence. 

2 » For such lamps tho inventor has discovered that the :>n«tndescmg: aaW 
should have the highest possiblo resistance in a very small 
resisting the disintegrating effects of very high heats in tho absence of otmospberio 
pressure, and further that carbons, which are purely structural in character alone 
possess theso qualities. By purely structural is moant a carbon wherein the 
[Price Is. 2c?.] A 












A.D. 1880.—N» 3765. 


Brewer's Improvements in Electric Lamps, do. 


natural structure, cellular or otherwise, of the original matorial is preserved 
unaltered, that it is not modified by any treatment which tends to fill up the cells 
or pores with unstructural carbon, or to incrcaso its donsity, or to alter its 
resistance. 

One object of this Invention therefore is to provide such enrbons, and means 5 
and methods for their manufacture. 

In practice the incandescing conductor of a lamp should bo of about one hundred 
ohms resistance, while this may be varied within certain limits; the resistance 
stated is a preferable one, and is a very high resistance compared to the enrbons 
referred to as previously used. 10 

It is essential that this high resistance should be had without increase of 
radiating surface, that is, only the radiating surfneo necessary to give a certain 
stnndnrd amount of light at the proper degree of incandcsconce should be used. 

Tho invontor has discovered tlmt incandescing conductors possessing the qualities 
enumerated may be made of such natural fibres or fibrous bodies as nro capable of 15 
carbonization, especially such ns are large, filamentary, and cellular in character. 

Of such there are several varieties, of some of which a single fibre or several lilacs 
aggregated together artificially are used, of some a piece composed of numerous 
elementary fibres is used. 

'Iho inventor has found Hint tho preferable single fibres are those of which jute, 20 
bast, manilla, hemp, nnd sucli like, nro good types, the most preferable one being a 
fibrous gross from South America called “ monkey bast ” fibre, each blado of which 
is generally round and composed of a great number of elomenlnry fibres held 
together by a natuial cement or resin, which carbonizing locks all tho elementary ^ 
fibres together into a homogeneous filament. Tho treatment next herein described 2» 
applies however to all the fibres of this class. 

Those blades vary somewhat in size and also are slightly tapering. It being 
necessary that the conductors should bo of a uniform sizo are reduced, and also 
any other fibres varying in sizo to uniformity by passing them through a cutting 
die, which shaves oil' tho extraneous matter; or a revolving cutter may be passed 
along the fibres, or they may be reducod in any othor practical way. 

When desired several blades of the above named grass, or several of any other 
natural fibres, may bo taken, and after bunching them together they are dipped 
into a solution of sugar or other carbonizable liquid and then carbonized as one 
fibre, tho carbonized cementing liquid binding them firmly together into n largo 3 
filament of higher resistance, but of no greater radiating surface than the 
carbonized paper incandescing conductor heretofore described by the inventor. 

Upon the ends of tho fibre, whether simple or compound, are fixed prior to 
carbonization clamps made of any suitable carbonizable matorial, lignum vit®, box ^ 
wood, or equivalent, being well adapted therefor. 

They may bo mado flattened or square, but preferably are cylinders. _ 

A small hole is bored through tho centre and tho fibre inserted therein. 

It is advantageous to moisten theso inserted ends of tho fibre with a solution o 
sugar or with other carbonizable liquid ; pieces of platinum wire are inserted in 
tho clamps. Upon carbonization tho material of the clamps shrinks around an 
upon tho wires and fibre, binding them tightly together, which result is aided J 
the carbonization of tho liquid applied as before suggested to the inserted end 
the fibre. . 

Of course materials wherein the pioco necessary to form a conductor is coinpo^ ^ 
of a largo number of fibres. Tho inventor has discovered that excellent rca 
pertain to the uso of tho plants of tho family arundensrin, or gigantic 6™^ 
commonly known as bamboo or cano, or cane bamboo. In such tho primary 
making up the mass of the material extend from end to end parallel to each • 
increasing the strength and obviating dunger of brcukngo from cross or o j j. 

Of the bamboo cane the hard glossy exterior is the best to uso, nud the softer or 
pithy interior part should be rejected. 


A.D. 1880_N° 3765. 


Brewer's Improvements in Electing Lamps, dc. 


To produce the best results in giving light it is essential that tho carbon should 
be of uniform sizo throughout tho portion that is to bo rondered inoandescont in 
order that radiating surfaco and resistance bo regular nnd uniform, ensuring oven 
heating nnd incandcsccnco. b 

S 1*1 ac . c 1 om P I * ah ‘ l,is t!l ° <™<>. bamboo, or other matorial used is treated as follows 
anil by tho following means :— 

The cane is split into pieces somewhat wider than necessary and tho inner or 
pith portion removed. The material chosen (either tho cano or bast, or other if 
desired) cut into strips is passed through a shaving dovico in which a cutting or 
10 shaving knife is fixed, tho material being forced against tho knife by a movable 
block provided with ail adjustable Btop screw, by which the distanco of the block from 
the knife can be regulated, regulating in turn tho thickness to be given to tho slip, 
is attained ° VlCC sll P or is slmveJ 011 botl ‘ sides until the proper thickness 

15 It is then placed in a clamp composed of two halves of a length equal to the 
desired length of the slip. In one half a shoulder or offset is made nt a distanco 
from tho edge greater than tho desired width, upon which ono edge of tho fibre 
rests which is then clamped between tho two halves and the protruding portion 
carefully shaved off, which may be dono by hand or by a cutting blade moved bv 
20 machinery. ° J 

On the opposito side of the clamp is an offset in ono half at a distanco from the 
edge exactly equal to the width to bo given tho slip. 

As it is desirnblo to form tho extended bearing upon which take the clamps 
securing the carbon to metallic conductors, homogeneous and in one pieco with the 
-5 body, provision is made therefor. 

Upon the sido last referred to of the clamps anil at tho ends are small projections 
of tiro exact shape and size to be given the broadened ends of tho carbons. 

The slip sliuved upon both sides and ono edge is transferred to tho opening in 
Ine clamps, and tho extra material shaved or cut off 
“ , Tl,c sli P is now of uniform size throughout its body and with enlarged ends 
formed upon it. 

These enlarged ends are entirely upon one edge, instead .of tho enlargement 
being equally distributed upon both edges, as elsewhere shown. 

Him construction enables tho slips when placed on edge, the straight edge, in 
0 the carbonizing flask to move therein, as they are contracted in the process of 
carbonization. 

Good natural anil purely structural carbons mny be made of wood, as the wood 
is an example of the class of material alluded to. m which the mass of material is 
composed of a number of elementary fibres naturally bound together. 

In all instances tho wood is first to be formed into the shnpe of what is generally 
known in the inventor’s system ns tho loop or “ horse shoe ” and then carbonized, 
cud not to be subjected to nny further processes which will tend to fill up its pores 
'"•'‘alter its density or resistance. 

Tho wood may bo prepared by several methods ; for instance, it can be shaped 
” cutting or stamping by a die. 

. , Mu veneer of wood, preferably smoother and brought to tho desired thickness, 
? ,ll kcnand laid upon a mould or bed plate, a cutting die is then forced down upon 
^/•Ging out a pieco in tho shape desired for the incandescing matorial, and 
50 , l'b thickened ends for attachment to tho clamps, or a number of vouoors may bo 
einul aDl * S0CIIIC ^ together, and then cut into proper shape by a band, gig, or 

Another method is as follows:— 

A block of wood is taken and cut or formed so that its centre shall bo a wob, 
55 .‘“'ded nt tho sides by thicker portions. The grain of the wood is from sido to 

c. aud tho thickness of the wob is about the desired breadth of tho carbon, 
thi I° m ^ 10 ^lock 80 fashioned pieces whoso width approximates the desired 

‘ckne3s of tho carbon nro split, shaved, or out off. Those pieces are then 

















4 A.D. 1880.—N° 3765. sSSSSSSi. 

Brewer's Improvements in Electric Lamps, etc. 

sufficiently softened by moisture and lieat so as to bo bent into a circular or horse 
shoe or ovnl form, and they aro retained in such slmpo in a proper carbonising 
flask and carbonized. 

Another method is ns follows:— 

A block of wood is taken ami out in a milling mnehino or lathe for turning 5 
irregular forms until its shape is that of an elongated oval, of which about one 
third, including an end, is cut upon somewhat larger axis than the remainder in 
order to provido for tho elatnps. 

Tlio interior is tlion reamed out in a suitablo mnehino, so tlmt tho block then 
resembles a series of carbon horso shoes with closed ends piled upon each other. 10 

Tho length of tho oval is with tho grain of tho wood. 

The block is then split or sawed into very thin layers or strips, each forming 
ultimately ono horso shoo carbon. 

The slips are then carbonized, preferably in a nickel flask. After carbonization 
the greater portion of tho broader end of the slip is cut off, leaving tho horso shoo 15 
in shnpe for use. This broader end, which connects what aro afterwards the ends 
of tho horso shoe, may, if desired, bo cut ofl prior to carbonization: but ns the 
broader connecting end tends to support and keep in slinpe the portions afterwards 
forming the horse shoo, it is better to leave it on until after carbonization. 

Either before or after carbonization, preferably before, and before tho slips aro 20 
sawed or split from tho block, small holes aro made in tho broad end, through 
which pass the clamp screws. 

It is desirable in manufacturing carbon slips or filaments of tho styles generally 
known ns tbc “ horse shoo ” carbons, for use as tho incandescing conductors in 
electric lights, that they should bo carbonized evenly and uniformly, and that their 25 
shape should be preserved that tho carbonization should be eflected without 
warping or twisting tho body of tho carbon. 

As however the material contracts largely ill the process of carbonization, means 
are required which, while holding tho material in position to avoid twisting or 
warping, shall at the same time guarantee even and thorough carbonization, and 30 
permit tho material to move, so tlmt the inevitable contraction during the process 
may proceed without danger of rupturing or otherwise damaging tho carbons. 

The means and methods for this object are as follows :— 

For fibres of the class where a single fibre is used and damps are secured thereto 
a carbonizing flask is used, in tho bottom of which is cut a groove approximating 35 
in form the shape desired for tho finished carbon, but somewhat longer, in which 
groove is laid tho fibro with its attached clamp. A heavy metallic cover is then 
laid thereon, confining the fibro in place, so tlmt it preserves its shape during 
carbonization, while at the same time it is freo to contract. 

Tho cover may in turn be grooved and receive another fibre, and a series bo M 
used, so tlmt many may be carbonized at once in one flask. This flask and all its 
parts should be made of nickel, which is best adapted to stand tho high heats 
necessary to thorough carbonization. . j 

Tho result is what is now known ns tho " horso shoo " carbon, made as n single 
fibre with carbon damps and proper conductors securely attached thereto by tho 
process of carbonization. j 

As theso carbon clamps from their much larger sizo relatively contain a largo 
quantity of deleterious gases, which cotno out very slowly when under tho 
of tho vacuum pumps, it iB preferable that clamps bo used which have first bo° 
carbonized and subjected in vacuo to heat sufficient to produce a high degreoi oi 
incandescence. When such aro used a very small amount of sugar applum to 
ends of the fibres servos, by its carbonization, to bind them securely together. 

The carbons mnde of the other materials set forth have enlarged onds «» 
upon them for offering a large and certain connection with tho clamps, as s 
forth. For thoir carbonization a flask constructed in either of the foflo" ° 
methods is used:— 

Those various forms are unitary in principle, in that they conGno and 

..-. .... /_ 



A.D. 1880.—N° 3765. 


Brewer’s Improvements in Electric Lamps, tie. 


the material during tho carbonization, proventing any distortion, while at tho snmo 
timo provision iB nmdo for contraction, and they differ only slightly in the details 
by which theso results are attained. 

In ono form a pinto is provided with a groove or recess of tho slmpo and sizo 
5 desired for tho carbons. At ono end of tho groove is a recess just largo enough to 
receive ono of tho enlarged onds of the strip, a pin being used to secure that end 
therein. At tho other end of tho groove is an elongated recess, tho excess of length 
of which is equal to tho contraction of tho material during carbonization, in which 
rests tho other ond of tho filament, to which may ho attached, or on which may bo 
10 placed, a smnll weight to keep it straight. 

During carbonization this end is drawn up in its elongated recess, the other end 
remaining fixed. 

In another form a groovo or rocoss is mado of tho elliptical form desired with 
recesses at tho onds just sullicicnt to admit of tho enlarged ends of tho filament 
15 placed sideways therein. 

Tho top or opox of tho groovo is enlarged in this case, ono boundary edge being 
upon a curvo equal to tho length of the uucarbonizod matorial, whilo tho other is of 
the length and slmpo desired for the filament after carbonization. 

In another form a recess is cut in a plate of tho form desired for tho carbon, but 
20 of a sizo tlmt will accommodate tho uucarbonizod material. 

In tho recess fits and slides a plato slightly smaller than tho recess, so that when 
tho plato is laid in tho recess a groovo is left sufficient in size to just receivo tho 
filament. 

Upon tho outer edges of tho recess and at tho proper points aro mado side recesses 
25 just largo enough to receivo tho enlarged ends of tho filament. The filament 
laid in tho groovo formod between tho r •*" ""' 1 “ 


___ _ and its plate, the enlarged onds laying 

in tho recesses provided therefore, weights being laid upon tho latter to confine 
them therein. 

During carbonization, as theso onds aro fixed, contraction draws down tho bow 
30 portion which carries tho plato with it, tho upper portion of tho plato preserving 
the shape of tho matorial. . 

The means described ousuro tho preservation of tho proper slmpo of tho material 
during cnrbomzation. 

It is also essential that they should bo carbonized ovenly and equally throughout 

This may bonccomplishcd by a furnace of the following description 

Preferably a nickel flask is used composed of two parts, a base plato provided 
with numerous le"s so as to support tho sumo and permit tho heat to reach tho 
bottom and a case, or which sets thereon. A series of plates constructed as 
M beforo described is placed upon tho bottom so ns to form a pile, and the box or caso 
placed thereon, its edges resting upon tho bottom. 

This flask !b then placed in an oven of a sizo sufficient to leavo a spaco on overy 
side of tho flask. . . ., 

Tho oven is provided with a top in which is a peep holo having a removable 
43 cover for inspection of tho interior. 

A pipo connected to a sourco of supply of any gaseous combustible passes around 
tho oven in sovoral branches, inlet pipes therefrom carrying the gas m as many 
places us necessary to tho interior of tho oven for coiusumption tlioro. 

A pipo connected to a suitablo air blast passes around tho ovon in the samo 
50 manner, from which lead branch pipes, ono passing into each inlet pipo of tlio gas 
supply, so that air under suitable pressuro is mingled with the gas at the point of 
combustion, furnishing the propor blast for ousuring tho necessary high dogroo of 

The gas and air pipes aro furnished with propor valves, so tlmt tho relative 

“Sythta“ wm tCsup^y bo 80 r0 S> datcd that at firsfc tho flask ia sub .i eotod 



















6 A.D. 1880.—N° 8765. 

oi*cdflcaUoQ. 

Brewer's Improvements in Electric Lamps, Ac. 

to n comparatively modorato heat only, which is then gradually brought up to tlio 
highest degree necessary. 

During tlio process of carbonization there is sometimes danger that tho materinl 
under treatment may bo ozidized to such an extent ns to intorforo with proper 
carbonization. 1 1 5 

This oxidntion is duo to tho oxygen in tho air present in the flnsk, and to tho 
oxygon eliminated from tho wood itself at the commencement of the process. 

If desired to prevent this, an auxiliary tube may ho used, passing into tlio flask, 
through which is introduced therein prior to firing, and during the burning, an 
atmosphere or hydrogen, or of somo hydro-carbon or of somu other element which 10 
will take up tho oxygen and prevent its action upon tlio filament. 

In a system of electric lighting, such ns proposed by tho inventor, in which 
soparato electric lamps devoid of regulating devices are used at tlio places of 
consumption, the entire regulation for nil tho lamps being performed at the control 
station, as with water or gas supply, it is essential that a constant eleclro-motivo 15 
force or pressuro be maintained. 

And as in such a system tlio Inraps are arranged upon tho multiplo nrc or derived 
circuit system, it is essential that there should be a certain standard resistance in 
each derived circuit. 

This has boon attained by placing ono lamp of such standard resistance in each 20 
derived circuit. 

It is desirable that all lamps used should bo of equal lighting value, each givings 
certain standard amount of light. ‘ 

This has been attained by giving each n certain definito or standard amount of 
radiating surface. 05 

Ordinarily this radiating surfneo lias been thnt with which tho standard pressuro 
or electro motive forco and tlio standard resistance should give a light equal to 1C 
candles. 

Sometimes however it is desirable in some part of tho system to uso lamps which 
each give a much less amount of light, for instance, in chandeliers, where it is 30 
desired to divide the total amount of light produced nmong a larger number of 
lamps than ordinary, that is, that the light of ono standard, say, 1C candle lamp, bo 
divided between two, three, or four lamps, each of eight, five, and ono third or 
four candle power respectively. 

This result may bo obtained in tho following way:— 35 

In a derived circuit nro placed two lamps, each being carefully provided with an 
incandescing^ conductor of ono half tho resistance and ono half tho radiating surface 
of the incandescing conductor of tho standard lump of tho system. 

A single circuit breaker is provided for both lamps, in order that both shall be 
turned off or on simultaneously. 40 

'When desirable, tho two lamps may bo arranged in one holder, which may form a 
bracket or a section of a group of lamps or of a chandilcr. 

Instead of two lamps as instanced, any number may be used, care being taken 
that the resistance of each be a fractional part of the standard resistance of ono 
ordinaiy lamp, tho denomination of the fraction boing the number of smaller lamps 45 
in tho one derived circuit. 

In tho lamp generally uBcd in my system and referred to hereinbefore, tho light 
is produced by the incandescence of a conductor in an hermetically sonlcd vessel; 
tho incnndescin^ conductor boing tho small carbon now generally designated as tho ^ 

Such howovor arc designed for small lamps, usually fifteen to eighteen candle 
power, and tho conductor required therefor boing small is hermetically scaled in 
ginss. 

When it is desired to produce on tho same principle a much greater light,say, 

ono hundred candles power, tho conductor theroto must also be much larger. 6 
Whilo tho inventor has succeeded t in satisfactorily sealing somowhat larger 


A.D. 1880.—N« 3765. 7 


Brewer's Improvements in Electric Lamps, Ac. 

conductors hermetically in tho glass, it is generally not so effective or desirable 
s method of passing largo conductors into tho bulb ns where small conductora are 
used, wherefore tlioro seems to bo a necessity for some other method, which, in the 
case of largo conductors, shall pass the conductors in tho bulb of the lamp without 
5 contact with tho glass thereof, and at tho sarno time furnish on effective and lasting 
hermoticnl soal. . 

This tho inventor 1ms succeeded in doing by the employment in tho lamp ot 
two colums of mercury sustained in tubes attached to the lamp bulb at ordinary 
baromotric hight by the pressuro of the atmosphere, and serving both as seals to 
10 preserve tho vacuum in tho lamp bulb, and as parts of the circuit through the 
iucandfscent conductors. . . 

A glass globo or bulb is blown of proper size, having an annular opening in its 
base of a sizo to admit of the passage into tho globo of an insulating base supporting 

15 After this base is put in tho globo tho annular opening is closed, and two tubes 
connecting with tho interior of the globe are connected hermetically thereto of a 
length somewhat greater than the baromotric column of mercury. 

From tho clamps of the carbon conductors pass ono from each clamp into the 
proper tube. . . . . . 

20 Tlio lower ends of tho tubes nro placed in proper mercury reservoirs insulated 
from each other, ono reservoir being connected to one pole of the source of 
electricity, tho other to tho other pole. .... 

The air being exhausted from tho globo, the mercury rises in the columns or 
tubes forming a seal for tho vacuum, and also forming a circuit to the conductors 
25 attached to tlio clamps. ... 

The lamp is supported upon or by a framo, the standards of which are provided 
with adjusting screws, so that its height may be regulated on the levelling of the 
stand secured. ... ,, 

Hitherto in manufacturing tho lamp the carbon, having been prepared from 
30 paper, wood, or other suitable fibre, was placed in the lamp, whose parts wore then 
scaled, tho lamp was then exhausted of nir, a current being applied during the 
process of exhaustion, heating tho carbon. . , , , , 

Prior to scalin" in tho lamp and the process of exhausting tho completed lamp 
the carbons wero not heated, and prior to heating any delects therein could not bo 
35 discovered. . , , , , 

It is practicably impossible to produce all tho loops or slips of absolute 
uniformity or homogenity.or to carbonizo all of them absolutely uniform throughout 

Whon^llentod 8 to redness, generally throughout their length, some show spots 
40 either loss red or of a brighter red than the average of the carbonB, indicating for 
tlio first timo faults in tho carbons. .... , . 

Where tlicro is a bad fault in the carbon a white incandescent appears 
determining tho lifo of tho lamp and also affecting its resistance. , 

Such lamps are unfit for use, and the entiro cost of their manufacture has proved 

11 The inventor now employs a simple and easy method and means of testing the 
carbons beforo they are put in tho lamp propor, and so prevent defect ve> or 
unsuitable carbons from being embodied in completed lamps to be only thrown 
away upon discovery of the fuults, increasing m fact tlio net cost of the faultless ones. 
50 Tins is accomplished by a preliminary heating of the carbons in vacuum, which 
l*y tho following means can bo cheaply, rnpidly, and efiectuiilly done. 

What may bo called a temporary lamp is formed of a globe or chamber.of proper 
size, with an aperture at its top of a size anil cient to admit of the passage of a 
carbon and its ‘supporting base. The neck of the supporting base pas cstightjy 
55 through a soft rubber cork which fits into the aperture m top of theg obe The 
cork is so sized that its upper side is a little distance below the top edge of tho 
aperture, so that when the cork is in position a chambor is formed on top. 

















8 A.D. 1880.—N° 3765. jftwuiwi 

bpcdflrmUon. 

Brewer’s Improvements in Electric Lamps, See. 

On ono side of the wall of tho aperture is an oponing having a tube upon its 
exterior, tbo opening being into the chamber referred to ns formed nbove the cork 
A mercury reservoir is connected to tho oponing by a floxiblo tube. 

When tho cork is put into placo tho resorvoir is elevated and tiio mercury flows 
thonco, forming a seal over the cook, per contra tho reservoir boing depressed tho n 
mercury flows back into the resorvoir, leaving tho cork oxposed, 

The globe is connected to a proper oxhaust tubo, sovoral springlo drops boine 
simultaneously used. 

By this means a carbon may be placed in tho globo, and soaled and exhausted 
quickly, and tho current nppliod for testing the carbon, and if found perfect it may 10 
be placed in a permanent lamjr. 

If the carbon proves defective it is discarded, tbo only loss boing tho labor and 
material, which are small, involved in tho manufacture of tho carbon, nnd not as 
hitherto, the material nnd great labor necessary to make a complote lamp. 

It is evident that several carbons may bo tested at onco in tho proving chamber 15 
or temporary lamp. 

One of tho objects in giving a very high resistance to the incandescing 
conductors used in my system of lighting is to attain economy of mnterial in tho 
conductors therefor. 

The resistance usually given them is sufficient for any desired economy in 20 
ordinarily thickly settled localities. For use, however, in sparsoly settled neigh¬ 
borhoods, as say, the outskirts or suburbs of a town or city, it may be desirable 
to have a lamp by the use of which still greater economy of conductor is attained. 

In such localities, in order to lessen tho number of lights needed in streots, it 
may be also desirable to have a lamp in which tho volume of light is increased, in 25 
order that economy in the erection of lamp posts, for examplo, may be subsorved, 
and it may also bo desirablo to uso lamps in which tho volume of light may be 
increased in other localities. 

As there is oventually a limit to tho cffectivo lifo of tho carbon used, it is desirablo 
to so nrrnngo a lamp that tho operativo lifo of tho lamp may be prolonged beyond 30 
the average life of a carbon, to the end that tho cost of the labor expended in 
embodying a carbon in a lamp may bo reduced. 

Both or eithor of these results are obtained in the following way 

In a globe mado and put togethor in tho mnnnor usually employed nnd hithorto 
described, two or more carbons are used. 35 

, J n “ S ‘ D S two to *ho end of ono conductor pnssing into and sealed in the globo 
is by its single limb fnstenod, a double clamp of Y shnpo to each of tho douhlo 
r a car ° on being attached. At their other end each carbon is attached to an 
individual clamp, each clamp boing attached to a conductor passing nnd soaled into 
tho globo. 40 

The conductors (in this instance threo in number) pass to a circuit closer con- 
necting them to tho conductor from tho source of electricity. 

. , H c i rou >t closer is so constructed as to bo capable of closing tho circuit 

simultaneously through both, and so that, as desired, they may bo eithor in ono 
circuit, as a sones, or each bo in its own derived circuit, or the circuit may he closod 45 
through either one separately. 

When both are used in multiplo arc, it is ovident that the net resistance 
of the circuit is ono half the resistance of one, and a certain sized conductor is 


When both are used in multiplo arc, it is ovident that the net resistance 
of the circuit is ono half the resistance of one, and a certain sized conductor is 
required. 

If both are used in series the resistance is double that of one, nnd four times 5' 
fourths ' he ““ tipl ° aro ' in whicl1 0080 tl10 conductor may bo diminished three 

As tho volume of light is that of two ordinary lamps, it is evident that a much 
less number may bo used with tho same light giving results. Thus economy m 
laying main conductors and in tho erection of lamps is secured. 

It is evident that, os one carbon only may bo usod at a timo, that by so using 
one only at a time, tho lifo of a manufactured lamp is practically doubled, for whore 


jSflSSS. A.D. 1880.—N° 3765. 0 

Brewer's Improvements in Electric Lamps, ito. 

ono carbon has reached its effective limit tho circuit thero-through is transferred to 
the othor, thus saving tho oxpenso involved in sealing ono carbon in its globo, tho 
cost of a globo, and its exhaustion. 

It is ovidonttlmt more than two carbons may bo sealed in ono globo, ono conductor 
5 being provided with the corresponding number of clamps, nnd each carbon provided 
with n separnto return wire, for which propor connections aro mndo by enlarging tho 
circuit closing key, on tho principle shown. 

In electric lamps formed by sealing an incandescing conductor hormotically in a 
glass enclosing globo, tlioro may bo danger somotimos that tho glass and wire will 
10 separate at tho point where tho conducting wires pass through and are sealed into 
the glass globo. This is duo to tho fact that tho conducting wires near tho 
incandescing mnterial becomo very hot by conduction, and that tho co-efficient of 
expansion of tho glass nnd wire are so different. 

In tho lamp mndo on this plan, owing to tho high resistance of tho incandescing 
15 material, such small conductors are used that tho danger referred to has boen of 
minor or tho very least importance. 

It may bo desirable, however, to provido means which reduce tho danger to a 
minimum, while affording at the same time tho necessary support for the very small 
nnd dolicalo conductors nnd incandescing material. 

20 To accomplish this, a small glass bulb is blown of a littlo larger diameter than 
the distance apart of the ends of tho carbon. 

Through this globo are pnssed and sealed therein tho conductors leading to tho 
carbon, each conductor boing scaled therefore in two places, one contiguous to 
tho clumps for receiving and supporting tho carbon, the other sonl being almost 
25 diametrically opposito. 

Tho carbon nnd clamps being placed in position, this small globo is placed in an 
aperture left for tho purpose in tho larger enclosing globo, and sealed thereto at 
about tho meridian lino of tho smaller bulb. 

Tho larger bulb is provided with a tubo by which it is attached to the air 
30 axlmusting apparatus, and where it is sealed after the vacuum is produced; con¬ 
nected to this tubo is a branch tube leading from tho smaller bulb, so that both aro 
simultaneously exhausted. 

As very small small conductors are used, it is necessary for stability that they bo 
supported near tho carbon, which is dono at tho sealings on top of tho smaller globe, 
35 but if either of these, from their proximity to tho light, is over so heated as to 
crack, it will still subservo its function as a support, while the vacuum is preserved 
by tho seals more distant from the clamps. 

Sometimes it may bo desirablo to make a lamp in which a less porinnncnt seal is 
used, involving a less expensive method of sealing, and which may bo taken apart 
40 readily for the substitution of a carbon, or for other purposes. 

This may bo dono as follows:— 

Upon a tubo closod at one end is supported a carbon, tho conductors therefrom 
passing through tho tube, and being sealed hermetically in tho top thereof. 

Tho enclosing globo is mado with a neck somewhat lurgor than tho tube, so that 
*5 the carbon may bo passed thorc-through. 

A rubber packing is interposed betwcon the outer walls of tho tubo and innor 
walls of the neck securing tho two together, tho ends of tho tube projecting beyond 
tho end of tho nock. . 

This projecting portion of tho tubo passes through tho base of a rubber cup, tho 
50 baso of tho nock resting upon tho bottom of tho interior of tho cup. At tho top of 
the clip a rubber packing Alls the spaco botween tho exterior of tho nock and the 
interior of tho cup. . .... , 

Tho spaco in tho cup is filled with mercury, which is retained in place in tho 
cup by tho packing last referred to, forming with tho rubber a good seal for any 
55 temporary use. 

















10 


BpwUtaUon, 


EpfcIflraUon, 


11 


A.D. 1880.—N° 3765. 

Brewer's Improvements in Electric Lamps, <ic. 


SPECIFICATION in pursuance of the conditions of the Lotters Patent filed by 
the said Edward Griffith Brewer in tho Grunt Seal Patent Office on the 
16th March 1881. 

Edward Griffith Brewer, of 33, Chancery Lnne, in the County of Middlesex, 

<• Improvements in Electric Lamps, and in Carbons or Incandescing 5 
Conductors therefor, and in Means for and Methods of Manufacturing 
the SAME.” A communication from abroad by Thomas Alva Edison, of Menlo 
Park, in the State of New Jersey, United States of America. 

As is now generally known said Edison prefers to uso in his system of electric 
lighting an electric lamp consisting essentially of an incandescing conductor sealed 10 
hermetically in a glass enclosing globo. 

In tho manufacturing carbons for such and for nil clnssos of electric lamps, the 
practice so far as known lias been to mako them of ns low resistance ns possible, a 
porous carbon having been used which was dipped or soaked in some cnrbonizablo 
liquid until its pores wero filled nnd then subjected to reenrbonization, which 15 
process was repeated until tho pores of the original carbon wero filled with 
carbon. 

By this process tho resistance of the carbon is lessened while its liability to 
disintegration under high bent is incrcnsed. Such carbons nro unfit for use in 
electric lamps giving light by incandescence. 20 

For such lumps said Edison has discovered that tho incandescing material should 
havo tho highest possible resistance in a very small bulk, nnd be capnblo of 
resisting tho disintegrating effects of very high heats and tho absonco of atmos¬ 
pheric pressure, and further that carbons which are purely structural in character _ 
alone possess these qualities. By purely structural is meant a carbon wherein the 2o 
natural structure, cellular or otherwise, of tho original material is preserved 
unaltered, that is, not modified by any treatment which tends to fill up the cells 
or pores with unstructurnl carbon, or to increase its density, or to alter its 

One object of this Invention therefore is to provide such carbons and means 30 
and methods for their manufacture. 

In prnctice tho incandesing conductor of a lamp should be of about ono hundred 
ohms resistance. While this may be varied within certain limits tho resistance 
stated is a preferttblo one, and is a very high resistance compared to the carbons 
referred to ns previously used. It is cssontial that this high resistance should be 35 
had without increase of radiating surface, that is, only tho radiating surface 
necessary to give a certnin standard amount of light at tho proper degree of 
incandescence should be used. 

Said Edison has discovered that incandescing conductors possessing the qualities 
enumerated may be made of such natural fibers or fibrous bodies ns arc capnblo of 
carbonization, especially such as nre large, filamentnry, and cellular in character. 

Of such there are soveral varieties, of some of which a singlo fibor or several 
fibers aggregated together artificially are used, of some a pieco composed or 
numornus elementary flbros arc used. 

Tho preferable single fibres are those of which juto, bast, manilla, homp, etc., ore 
good types, tho moro prefernblo one being a fibrous grass from South America 
called 11 monkey bast ” fibre, each blade of which is generally round nnd composed 
of a grant number of elementary fibres held together by a nnturnl cement or 
resin, which carbonizing locks all the elementary fibers together into a homogeneous 
filament. The treatment next herein described applies however to nil tho fibers 
of this class. These blades vary somowbnt in size nnd nro also slightly taporiog. 

It being necessary that the conductors should bo of an uniform size tboy nro 


Brewer's Improvements in Electric Lamps, <L-c. 


reduced, and also any othor fibers varying in size to uniformity by passing them 
through a cutting die which shaves ofT tho extraneous matter, or a revolving cutter 
may bo pnssed along the fiber, or tlioy may bo reduced in any other practical 

5 When desired, seveal fibers of tho above unmcd grass or several of any other 
natural fibers may bo tnkon, and after bunching them together dip thorn into a 
solution of sugar or other cnrbonizablo liquid nnd then carbonize as one fibor, 
the carbonized cementing liquid binding them tightly together into a largo 
filament of higher resistance, but of no greater radiating surfaco than tho carbonized 
0 paper incandescing conductor lieretoh.ro patented by said Edison. So far os 
capable of illustration this part of the Invention is shewn in Figs. 1, 2, & 3. 
Upon tho ends of the fiber A, whether simple or compound, nre fixed prior to 
carbonization, the chimps B made of any suitable cnrbonizable material, lignum 
vitae, box wood, etc., being well adapted therefor. They may be made flattened or 
5 square, hut preferably are cylinders. A small hole is bored through the center and the 
fiber inserted therein, ns shown in Fig. 2. It is advantageous to moisten tho 
inserted ends of the fiber with a solution of sugar or with othor cnrbonizable 
liquid. Pieces of platinum wiro c, o, arc inserted into tho clamps, as shown 
in Fig. I. Upon carbonization tho material of damps B, B, shrinks around, 
!0 nnd upon tho wires nnd fiber binding them tightly togothor, which result is 
aided by the carbonization of tho liquid applied, as before suggested, to the 
inserted ends of the fiber. Of those materials wherein tho pieco necessary to form 
a conductor is composed of a lurgo number of libers, excellent results pertain to tho 
use of the plants of the family arimdeneria or gigantic grasses commonly known 
5 as bamboo or cane or cane bamboo. In such the primary fibers milking up tho 
mass of the material extends from end to end parallel tc 
strength and obviating danger of brcakago from cross 
bamboo cane the hard glossy exterior is the best to u 
part should be rejected, 
if) To produce the best results in giving light, it is essential that the carbons should 
he of uniform size throughout the portion that is to bo rendered incandescent, in 
order that the radiating surfaco and resistance bo regular and uniform, ensuring 
even heating and incandescence. To accomplisn this, tho cane, bamboo, or other 
material used is treated as follows, and by tho following means :—The cane is split 
15 into pieces somewhat wider than necessary, and the inner or pith portion removed. 
’The material chosen (either tho caso or bast, or other if desired) cut into strips, is 
passed through a shaving device, in which a cutting or shaving knife is fixed, tho 
material being forced against tho knife by a movable block provided with an 
adjustable atop screw, by which tho distnneo of tho block from the knife can be 
0 regulated, regulating in turn tho thickness to bo givon to the slip. Ill this device 
the slip or filament is shaved on both sides until llio proper thickness is attained. 
It is then placed in a clamp composed of two halves, of a length equal to the 
desired length of the slip. In one half a shoulder or offset is formed at a distance 
from tho edge greater than tho desired width upon which one edge of the fiber rests, 
:5 which is then clamped between tho two halves, and the protruding portion carefully 
shaved off, which may bo dono by hand or by a cuttiug blade moved by machinery. 
On the opposite side of tho clamps is an off-sot in one half, at a distance from tho 
edge exactly equal to the width to bo given the slip. As it is dosirnblo to form 
the extended bearing, upon which take tho clamps securing the carbon to inotallio 
'0 conductors, homogeneous and in ono piece with tho body, provision is made therefor. 
Upon the side last referred tp of tho clamps and at the ends are miido projections of 
tho exact slmpo nnd sizo to lie givon tho broadened ends of tho carbons. Tho slip 
shaved upon both sides, and ono edgo is transferred to tho opening in the clamps, 
and tho extra material sliavod or cut off. The slip is now of uniform sizo throughout 

. - - • The enlarged ends are entirely upon 

.. ,. .--■i— i-.i - edges. 


o each other, increasing the 
or oblique grain. Of tho 
e, and the softer or pithy 


its body, with enlarged ends formed upon it. The enlarged ends are entirely tj] 
one edge instead of the enlargement being equally distributed upon both ed; 
This construction enables the slips whon placed on edge, tho straight edgo in 

















Specification. 


12 A.D. 1880.—N° 3765. spoliation. 


Brewer's Improvements in Electric Lamps, <fco. 

carbonizing flask to movo tlieroin ns tlioy nro contracted in tbo process of carbon¬ 
ization. This pnrt of tbo Invontion is illustrated in Figs. 4, 5, 0, 7, and 8, in which 
Fig, 4 is a top viow, and Fig. B is a side view of tho dovico used for shaving tho 
sides; Fig. 0 is an ond viow, and Fig. 7 is a side view of tho clamps used in shaving 
tho edges. Fig. 8 is a viow of a comploto filnmont. 5 

In these Figures, A is a suitable base, having upon it supports a, a\ for tho 
working doviccs, these supports leaving an open space between them in which such 
working devices nro mainly located. In front of a 1 is fixed a block 33 fashioned at 
ono end to recoivo and support nt tho proper angle tho knifo or plane b. In front 
of a is a block C attached to screw D sliding in a, and caused to rotate so as to 10 
movo C by disk E, working in a Blot in a, 1), boing prevented from rotating by 
Berew d taking into a feather cut in its side. Upon the sido of C is lug 0, through 
which passes tho scrow tj, which is set to strike against B, and consequently limit 
the movement of C, keeping it at any desired distance from B, which distance is tho 
thickness to be given tho slip. The slip s is placed between B and C, and 15 
drawn through between them, being forced by C against tho edgo of the kidfo 
until one sido is smoothed. It is then taken out and replaced with tho shaved sido 
next to c, and the operation repented. 

By theso operations and monns tho slip is reduced to an uniform thickness. 

Tho clamp for reducing to an uniform width is made of two parts II, I, of a 20 
lougth equal to tho length to bo given to tho slip, and held together by pieces x 
ono at each end, hnving a slot o in ono end so as to permit of a limited movement 
of the parts H, I, from each other. 

Tho part I is formed with shoulders or off sots v, w, nlong its ontiro length, 
taking into a corresponding recess in II, forming when tho two parts aro in position 25 
Blots along tho entire length of tho clamp, tho oil' sets v, w, forming the bottom of 
tho slots. Upon ono side at each end of each pnrt aro formed the lugs or 
projections h, h, tho size and shapo of tho enlarged ends of tho finished carbons. 

In h, h, tho small recesses i, i, for the purposes hereinafter set forth. 

Tho slip S of a greater width than the widest portion of the finished slip is 30 
placed in the clamp in the slot, whoso bottom is tbo off set v, the clamps tightened 
and the protruding portion removed down to tho surfneo of the clamps. The edge 
thus prepared forms a straight edge or gage for the finishing, tho slip being placed 
in the clamp in the slot whose bottom is the ofl set w, and tho extra material 
removed on tho line formed by tho surface of tho clamp and tho projections li. It. 3o 
This being done a saw or knifo is run through tho recesses i, i. The result is 
the slip shown in Fig. S having an uniform body with tho enlarged clamps for 
securing the carbon in the clamps, and provided with the recesses i, which are of 
use in securing the slip in the carbonizing flask, and afterwards for permitting 
tho clamping screws to pass through. Sometimes it is dcsirablo to form tho ends 40 
thicker in both directions. In such coses tho preliminary cutting in the first 
machino simply reduces the slip to dimensions equal to tho desired width ami 
thickness of tho ends, and it is then finished off in the clamps, ono set ot clamps 
being made with shallow grooves so that the slip may bo laid flatwise thoioin. Boon 
natural and purely structural carbons may bo mndo of wood, ns wood is an example 4o 
of tho class of materials alluded to, in which tho mass of material is composed 
of a number of elementary fibers naturally bound together. In all instances tho 
wood is first to be formed into tho shape of whnt is generally known in KtlisoM s 
system, as the loop or " horse shoe,” and then carbonized, and not to be subjected 
to any further processes which will tend to fill up its pores and alter its density o 
or resistance. , 

Tho wood may bo prepared by several methods, for instanco, it can be shaped oy 
cutting or stamping by a die. A thin veneer of wood properly smoothed an 
brought to the desired thickness is taken and laid upon a mold or bed put > 
a cutting die is then forced down upon it cutting out a piece in tho desired snap 
for the incandescing mnterial, and with thickened ends for attachment to t 
clamps, or a number of veneers may bo taken and secured together, and then eu 


A.D. 1880.—N° 3765. 


Brewer's Improvements in Electric Lamps, Ac. 


into proper shapo by a band, jig, or circular saw. This is illustrated in Fig. 0, 
which is a section of the cutting dio and mold with a veneer in position, and in 
Fig. 10, which shows tho resultant piece ready for carbonization. In these Figures 
A is a cutting or stamping dio provided with tho cutting or stamping edge a 
s projecting from tho face of A, and of the samo size and contour as tho woodon horse 
shoe E; B is the mold or bed-plnto having a groovo or recess D, whoso upper edge 
is of a Bizo and Bhnpe just sufficient to receive a, but increasing in aizo towards tho 
huso to permit tho ready escape of anything which may bo forced in at the top. 

0 is a piece of voncer in position for tho operation of the stamp or die A. upon 
10 forco being applied to A shoo E is cut from the wood, with the broadened otids c 
for attachment to the clamps homogeneous and unitary therewith.. Ibis in then 
taken and placed in a suitable carbonizing flask fully illustrated korem. The result 
is a porous structural carbon of high resistance excellontly fitted for use in lamps 
intended to give light by incnndesconcc, and not needing any further treatment 
16 which might alter or modify its purely natural structure. Another method is as 
16 follows A block of wood is taken and cut or formed so that its center shall ho a 
web bounded at the sides by thicker portions. The grain of tho wood isfromside 
to side, and tho thickness of tho web is about tho desired breadth of the carbon. 
From tho block so fashioned pieces whoso width approximate the dosu-ed thick esa 
20 of the carbon aro split, slowed, or cut olf These pieces are then sufbc.cntly 
softened by moisturo and beat, so ns to bo bent into a circu a , <> 

oval form, and they are retained in such shape in a proper enibomzmg flitsk and 

carbonized. This method is illustrated ill Figs. 11, 12, A Id, m which Ii„. 
represents a block formed as before described ; F ig. 12, a piece split cut or shaved 
25 therefrom and Fig. 13 tho same after carbonization, in which A is the web of the 
block, the’ center o^f the block being reduced in thickness, "’ hl . lo t l ® °"? S “’ sh ; vcd 
left broad or thickened for fastening to the clamps This block is 13 0 r 

into pieces like Fig. 12, which are then bent into the shape shown in F g. 13, or 

into i nv other desired shape and then carbonized while in such form, ihe lesult 

3() .. c .,..p 0 .. v .; t p ... ends for clamping unitary with itself, and wlncli is 

it it . i c ro'iistunce and with a minimum tendency to 
porous, structuraliy unaltered, oE mgn lesistanct, aim n cou u 


latho for turning irregular form , 

which about one third, including an end, is cut reamod out h, 

remainder in order to provide for tho flumps., xne . . , *— 

0 a suitable machine, 

of the wood.”The block is then split or saweu inio m, 
forming ultimately one horse shoe «jrbon. J heso^slips, 


;s of carbon horse shoos 


so that the block then resembles ast 
. each other. The length 
s then split or sawed il 

“ E» E“" nftrSiilji* SJ.SSuS 

tlie horse shoo may it desired bo cut oil pnoi to .. a ft er wards forming 

screws. This is illustrated in Figs. 11 1 10 .“ b 

perspective viow of tho block partially turned m P I I f . s ; do v ; ew 0 f 
Fig. 15 is a front view of a carbon after carbonization ,F 10 is^s _ ^ ^ 

65 a carbon properly secured in damps. ^ ^ q . g that ofan 0 val 

ikS: o, s si. * 















14. 


for tho clumps, the interior boing reamed out to present a uniform smooth 
surface F. 'J'liis block so shaped is then split or sawed into very thin layers or 
slips of a thickness sufficient for ono carbon horse shoe, ns seen in Figs. 15 and 1G. 
Thcso slips are then carbonized and a portion of C broken or cut off at c, c, as shown 
in dotted lines in Fig. 15. At some stages in tho process, proferably while in the 5 
shape shown, in Fig. 14, holes d, d, are drilled for tho reception of tho 
screws e, which fnston tho clamps D to tho carbon. It is dosirablo in manu¬ 
facturing carbon slips or filaments of tho style generally known ns tho horse shoo 
carbons for use as tho incandescing conductors in electric lights that they should he 
carbonized evenly and uniformly, and that their shape should bo preserved, that 10 
the carbonization should bo effected without warping or twisting tho body 
of the carbon. As however tho material contracts largely in tho process of 
carbonization, means arc required which, while holding the material in position 
to avoid twisting or warping, shall nt tho same time guarantee oven and 
thorough carbonization and permit tho material to move, so that tho inevitable 15 
contraction during tho process may proceed without danger of rupturing or 
otherwise damaging tho carbons. For this purpose means and methods ns follows 
arc used:— 

For fibers of tho class where a singlo fibor is used and clamps or enlarged portions 
for clamps nro secured thereto, a carbonizing flask is used, in tho bottom of which 20 
is cut a groovo approximating in form tho shape desired for tho finished carbon, 
but somewhat longer, in which groove is laid the fiber with its attached clamps. A 
heavy metallic cover is then laid thorcon confining the fiber in placo, so that it 
preserves its shape during carbonization, wliilo at tho same time it is lice to 
contract. The cover may in turn be grooved and receive another fiber, and a series 25 
be used so that many may bo carbonized at onco in ono flask. This flask and nil 
its parts should bo made of nickel, which is best ndnptcd to stand the high heats 
necessary to thorough carbonization. 

This flask is illustrated in Fig. 17, in which D is n flask or box of metal capable 
of withstanding a high degree of heat, having ft groove E of the desired shape cut 30 
in its bottom, as shown in Fig. 17. As fibrous material contracts or shrinks in tho 
process of carbonization, it is necessary to provido for tho movement attendant 
thereon, care boing taken at the same time to prevent any movement which would 
allow of warping or distortion. This is effected by tho groovo E which allows a 
longitudinal movement but prevents any other. In this groovo tho fiber with its 35 
attached ends is placed, a cover F being then laid over it. A corresponding groove 
may lie cut in tho upper surface of tho cover F and nnotlier fibor laid therein, mid 
a number of such covers, limited by the capacity of the flask or box D, may he 
used, so that many may be carbonized at one operation. When the (lask or box 1) 
is full the lid F l is fastened tightly thereon, and tho whole placed in any suitable 40 
furnace for carbonization. Tho result is what is now known as tho liorso shoo 
carbon made as a singlo fiber with carbon clumps and proper conductors securely 
att..cl.cd thereto by the process oi carbonization. As these carbon clamps from 
their much larger Bize relatively contain a large quantity of deleterious gases, which 
come out very slowly when under the action of the vacuum pumps, it is preferable 45 
that clamps bo used which have first been carbonized and subjected in vacuo to 
heat sufficient to produco a high degree of incandescence. When such nro used a 
very small amount of sugar appliod to tho ends of the fibers sorves by its carboni¬ 
zation to bind them securely together. 

The carbons made of the other materials sot forth have enlarged ends made upon 50 
them for affording a large and certain connection with tho clamps, os 6et forth. For 
their carbonization a flask constructed in either of the following methods is used:— 
liieso several forms are unitary in principle in that they confine and support the 
material during its carbonization, preventing any distortion, while at the same time 
provision is made for contraction, and they differ only slightly in tho details by 55 
which these results are attained. In one form a plate is provided with a groove 
or recess of the Bbape and Bize desired for the carbon. At ono ond of tho groove is 



BpwlflciUoo. 


A.D. 1880.—N° 3 


Brewer's Improvements in Electric Lamps, Ac. 


a recess just large enough to receive one of the enlarged ends of the strip, a pm 
bcinc used to socuro that ond therein. . 

At the other ond of tho groovo is an elongated recess, whose excess of length is 
enuttl lo tho contraction of the material during carbonization, in which rests tho 
5 other end of tho filament, to which may bo attached or on which may be placod a 
small weight to keep it straight. During carbonization this end is drawn up in its 
elongated recess, tho other end remaining fixed. In another form a groovo or recess 
is made of tho elliptical form desired, with recesses at tho ends just suflicicnt to 
admit of tho oiilarged ends of the filament placed sideways therein. The top or apex 
,0 of tho groovo is enlarged in this case, one boundary edge being upon a curve equal 
to tho length of tho uncarbonized material, while tho other is ot the length and 
shape desired for the filament after carbonization. „ ,- nf 

In another form a recess is cut in a plate of tho form desired for the onn but 
of a size that will nccomodato the uncarbomzed material. In the lcc ““ h " TJ 
15 slides a plate slightly smaller than the recess, so that when the j.late s laid m the 
recess a groovo is left sufficient in size to just receive the filament. Upon. the outer 
edgo of the recess, and at the proper points, are made side recesses J ,3t * al =“ e = 
torccoivo the enlarged ends of the filament. The filament is hud in tl o gice 
formed between the recess and its plate the enlarged endslaying Durin „ 

of the material. These plans may be bettor understood by leferencoto .18, 
19 20 21,22,23,24, 25, and 2G, in which l'igs. 18, 21,-4, ami _o nro pm 
25 of carbonizing plates, unitary in principle but ditlerm^ shshtly m ““‘"I;. J ^ 
n ,,,i (,, 1 ,,,. and side view respectively of a slip or filament rc.iuy rar uu 

30 “u ‘I" U.e'TensufSS W t^ffin'is lied'carbrnfi 

pluf th" contraction of the material during ,to a 

Fig. 18 this extra length is at ono end of the g , ' ^ g of thu ,j la „ le „t, 

small chamber just sufficient to loceue om. ot 1 A P 1 need in the 

35 Which is secured therein by a pin e a 

cl a nbor to assist in keep ng the onln^ end « g >' ■ X J,lr 6, wlmse length 
•" d/ , T 10 in U.,, st l. ..f the filament in 

• *SU a -«. -ip - ..- r «=2 

by a smooth plate, or a series ma. U- .i.o underneath. They arc then 

under surface of one forming the covti ^ subjl . ctl ,d to the first low heat 

placed in a smtublo nickel cast., and o = dually tluonghout each slip or 

45 carbonization and contraction proceed e\ eii y d ^ uulU , a t | 1B 

filament, the contraction drawing up the 1 ;t xiio cases and plates 

«»•* 

50 Tis shown formed with a chamber «‘ at the bow of tho 

horse shoe. •. -,-nnve the ends c, c, fitting into 

In this case the slip s is hud (bitwise m tl g■ ^ ^ jj y tlli3 mean3 
chambers at the end of tho groove, upon w 11 S w)lile t | l0 con traotion is 

























16 A.D. 1880.—N° 3766. speculation. 

Brewer's Improvements in Electric Lamps, i to. 

the plato A is formed with a chamber, in which slides a plate C smaljer than the 
chambor by tho sizo of the filament or strip, so that when tho plato C is placed in 
tho chamber a groovo shall bo left in which is placed tho filament or strip, tho 
onds c, c, resting in chambers fitted for them, and held in place therein by woights 
<7, g, laid thereon, in chambers mado thorofor. 5 

As the filament is thus fastened at tho onds, ns carbonization proceeds, tho 
ensuing contraction pulls tho bow towards tho onds forcing tho plato C towards 
the end B of A. In all thoso plans, howovor, tho filament is kept under strain 
during carbonization with ono or moro points fixed against moving, and tho 
contraction proceeds agninst tho strain which constantly keeps tho filament against 10 
or in contact with a former, preserving its shape and obviating any risk of warping 
or twisting. In all provision is mado for keeping flat and in their propor relative 
position the enlarged ends of tho carbon. 

It is also essential that they should bo carbonized ovenly and equally throughout 
their entiro mass. This may bo accomplished by a furnace of tho following 15 
description :—Preferably a nickel flask is used composed of two parts, a base plate 
provided with numerous legs so ns to support tho snmo and permit tho heat to 
reach tho bottom, and a case or box which sots thereon. A series of plates, 
constructed ns before described, is laid upon tho bottom so as to form a pile, and 
tho box or case plnced thereon, its edges resting upon tho bottom. Tho (lask is 20 
then placed in an oven of a size sufficient to lenvo a spaco on every side of the flask. 
Tho oven is provided with a top, in which is a peep-hole, having a removable cover 
for inspection of tho interior. A pipe connected to a source of supply of any 
gaseous combustible passes around tho oven in several branches, inlet pipes 
therefrom currying tho gas in as many places as necessary to tho interior of the 25 
oven for consumption thcro. 

A pipe connected to a suitablo air blnst passes around tho oven in tho same 
manner, from which lead branch pipes, ono passing into each inlet pipo of the gas 
supply, so tlint air under suitable pressure is mingled with tho gas at tho point of 
combustion, furnishing the proper blnst for ensuring the necessary high degree 30 
of heat. Tho gas and air pipes nro furnished with proper valves, so that the 
relntive supply of each may bo regulated. By this means the supply may be so 
regulated that at first tho flask is subjected to a comparatively moderate heat only, 
which is then gradually brought up to tho highest degreo necessary. 

The carrying into client of this part of the Invention may bo more clearly 35 
understood by reference to Figs. 28, 29, and 80, of which Fig. 28 is a view of a 
carbonizing plato grooved to receive a filament; Fig. 29 is a perspective view of 
a series of the plates in the carbonizing flask; Fig. 30 is a perspective view of the 
carbonizing oven. In these Figures, A is a carbonizing plate grooved to receive a 
filament, and to havo it secured therein. The carbonizing flnsk is composed of two 40 
portions, B and C ; B is a base provided with numerous legs b, b, b, t>, in order to 
raise it above tho bottom of tho oven to permit tho free passage of heat there 
around. Upon B is arranged a series of tho plates A, each containing n filament, 
and over the series is placed a cover C, securing them all upon tho base and witluu 
the flask. The flask so filled is placed within tho oven D, provided with tho 4o 
cover E, an exit e for the escapo of tho products of combustion being provided. A 
peep hole maybe provided, which is closed by cover F, through which tho condition 
of the flnsk mny bo observed. A pipo G, connected to a source of supply of any 
gaseous fluid, passes around tho oven in sovcral branches, inlot branches </, 
therefrom conveying the gas in os many places ns necessary to tho interior of the o 
oven for consumption ; 11 is an air tubo connected with a suitablo blast and passing 
around the oven in tho snmo manner as O, from which lead branch pipes It, «> «> 
ono passing into each branch inlot g, so that nir under pressure is mingled with tlw 
gas at tho point of combustion, furnishing a supply of air for proper combustion, 
and ensuring tho necessary high degree of heat. Both G and 11 are provided with 
ordinary stop cocks or valves, by which tho supply of cither nir or gas absolutely 
or relatively to each othor mny bo regulated. Tho oven D is of such a sizo tllM 


Brewer's Improvements in Electric Lamps, ,ic. 


tho flask and tho oven. The flask, filled with plates and filaments, is placed in tho 
ovon and tho firo kindled by lighting tho gas. By moans of the valve before 
inentionod, tho supply of fuol mny bo so regulated that at first tho flask is subjected 
5 to a moderate boat, which may bo gradually brought up to the required point. 
The blast onsures a high degreo of heat directed immediately upon the flnsk, and 
evenly distributed thereon. 

When heated for a sufficient time tho gas is turned ofT, and the flask mny bo 
allowed to cool down in tho oven. During tho process of carbonization there is 
10 sometimes danger that tho material under treatment may he oxydized to such an 
extent as to interfere with proper carbonization. This oxydution is duo to tho 
o'xyuen in the air present in tho flask, and to the oxygen eliminated from tho wood 
itself at tho commencement of the process. If desired to provont this, an auxiliary 
tube may be used, passing into the flask, through which is introduced therein prior 
15 to firing, and during tho burning, an atmosphere of hydrogen, or of soino hydro 
carbon, or of some othor element which will take up tho oxygen and prevent its 
action upon the filaments. . ... 

In a system of electric lighting, such as proposed by said Edison, in wliicli 
separato electric lamps dovoid of regulating devices are used at tho places ot 
20 consumption, tho entire regulation for all the lamps being performed at the central 
station as with water or gas supply, it is essential that a constant electro motivo 
force or pressure be maintained. And as in such a system tho amps are arranged 
upon the multiple arc or derived circuit system it is essential that there should be 
a certain standard resistance iu each derived circuit This has been attained by 
25 placin'- ono lamp of such standard resistance in each derived circuit. It is desirable 
that all lamps should bo of equal lighting value, each giving a ce. tain standard 
amount of li-lit. This has been attained by giving each a certain definite or 

11 ^ 
30 or electro motive force and the standard resistance should give a light equal o 

sixteen candles. Sometimes however it is desirable in some parts o us sys en 
use lamps which each give a much less amount of light; for instance, m chiindtl -i* 
where it is desirable to divide tho total amount ot light produced among a la,ge 
number of lamps than ordinary, that is, that the light of one, say, standard sixteen 
35 candle lamp, be divided between two, three, or four amps, each of eigl . fivc 
and one third, or four candle power respectively. This result may be attained 

* U In'a^deri'vedPcircuitare placed two lamps, each being orwefully previded with 
on incandescing conductor of one half the resistance and 000 > m f ? 

10 surface of the incandescing conductor of the standard amp of t « ) ' 

single circuit breaker is provided for both lamps in order that both shall bo turned 
olf or on simultaneously. 1 ^ When desirable the two lamps may be arra ged n on 
holder, which may foimr a bracket or may &nn a ° 3a greup of lamps orjf 


w surface ol the incandescing conaucioi oi mo hn fnrnpd 

single circuit breaker is provided for both lamps in order that both shall bo^ turned 
Olf or on simultaneously. 1 ^ When desirable the two lamps may be arra ged n on 
holder, which may form a bracket or may form a section of a 8™“ 

, «chandelier. This part of the Invention is shown ml'igs. 31, 3-, and Jd. « bore n 

53 «hicl, A would give. If it is desired to increase the njjmtar th sir 

between tho number used and tho standard resistance ami 1 at g urUrem>fi° 
exist. For two, three, or more lamps a suitablo holder if ot insuiatin 0 mure.iar 






















18 A.D. 1880.—N° 3765. speculation. 


Urn warn Improvements in Electric Lamps, <0 ft 

made, sockets s lioing made tlierein for encli lamp. To each sockot metallic 
conducting plntes tiro placed on oppusito sides, as at c, c 1 , d, d\ for forming contact 
with metal slips or pieces on the necks of the lamps. The socket may be provided 
with a plain or screw threaded nperturo 1C, by which it mny bo attached to the wall 
as a bracket or to a framing so that it may constitute a portion of a group of 5 
lamps or of a chandelier. Upon tlm socket is a circuit breaker consisting of a 
metallic screw D securod in a seat h, and which may bo turned to impinge upon or 
bo cleared from contact with a metal block e. Tho conductor C passes through c, o', 
to e, and the conductor C 1 through d, d\ to tho metal soal h of tho scrow D. 

Instead of two lamps ns instancod, any number may bo used, care being takon 10 
that tho resistance of each be a fractional part of the standard resistance of ono 
ordinary lamp, the denominator of the fraction being'tho number of smaller lamps 
in the one derived circuit. If more than two are used, the block e and screw I) are 
placed somewhere in the circuit, loading through all the lamps in order that all mny 
be turned on or off simultaneously, all tho divided lamps being used ns ono 15 
stnndnrd lamp. In the lamps generally used in said Edison’s system, and referred 
to herein before, the light is produced by tho incandescenco of a conductor in an 
hermetically sealed vessel, the incandescing conductor being the small carbon now 
generally designated ns tho " horse shoe carbon." Such, however, are designed for 
small lamps usually, say, fifteen to eighteen candle power, and the conductor 20 
required therefor being small is hermetically sealed in glass. When it is desired to 
produce on the same principle a much greater light, say, ono hundred candle power, 
tho conductor thereto must also be much larger. While said Edison has succeeded 
satisfactorily in sealing somewhat larger conductors hermetically in the glass, it is 
generally not so cflective or desirable a method of passing large conductors into the 25 
bulb ns where small conductors are used. Wherefore, there seems to bo a necessity 
for some other method, which in the case of larger conductors, shall pass tho 
conductor into the bulb of the lamp without contact with the glass thereof, and at 
the snmc time furnish an effective and lasting hcrmctical seal. This is accomplished 
by tire employment in the lamp of two columns of mercury sustained in tubes 30 
attached to the lamp bulb at ordinary barometric bight by tire pressure of the 
atmosphere, and serving both as seals to preserve the vacuum in tho lamp bulb nnd 
ns parts of the circuit through tho incandescent conductors. A glass globe or bulb 
is blown of proper size, having an annular opening in its base of a size to admit of 
tho passage into the globe of an insulating base supporting the carbon. After this 35 
base is put in the globe, the annular opening is closed, and two tubes connecting with 
tho interior of tho globe are connected hermetically thereto, of a length somowhat 
greater thnn the barometric column of mercury. From tho clamps of the carbons, 
conductors pass one from each clamp into the proper tube. The lower ends of the 
tubes arc placed in proper mercury reservoirs insulated from each other, ono reservoir * 
being connected to one pule of the source of electricity, the other to tho other pole. 
Tho air being exhausted from the globe, the mercury rises iu tho columns or tubes, 
forming a seal for tho vacuum, and also forming a circuit to the conductors attached 
to tho clamps. Tho lamp is supported upon or by a frame, whoso standard., are 
provided with adjusting screws, so that its bight may be regulated, or tho leveling 0 
of tho stand secured. , 

This part of tho Invention is shown in detail in Fig. 34, which is a viow of a 
lamp embodying this part of tho Invention, shortened somewhat in proportion to 
its hight, ns indicated in the dotted line. A glass globo or bulb A is blown, having 
an annular opening in its base of a size to admit of tho base ct, a, passing there- ■ 
through. Tho lino of this opening is indicated at i, i. Upon tho top of tho bulb is 
formed a tube, tho continuation of tho projection N by which the lamp is attache 
to the air pump. Upon a suitablo base a, a, of insulating material are fastened oy 
proper devices, the clamps b, b, holding nnd supporting tho horso shoo B, tho clan'F 
being connected to motnllie conductors c, o', passing a little distance, say, several 
inches, below the base a, a. Two gluss tubes o, o', each of a diameter sevoral time 
greater than that of e or e 1 , and several inches longer thnn a column of mercury 


A.D. 1880.—N" 3765. 


Brewer 'b Improvements in Electric Lamps, d-c. 

supported in vacuo by atmospheric pressure, nro united near their top ns at m, nnd 
their united tops formed into a circle, the diameter of or slightly larger than the 
diameter i, i, of the opening in A. The base «, a, supporting tho carbon and with 
its attached conductors is introduced into A, ami the tubes c, c 1 , are then secured 
5 by sealing at i, i, to A ; tho conductor e projecting downwardly intoc, ande 1 into o l . 

For supporting the lain]) thus formed a stand is employed consisting of an 
insulating top Ii nnd baso E 1 united by metallic standards F, F 1 , which are 
connected to the base E 1 by adjustable screw connections rj, p l , so that, as 
circumstances require, tho top may bo raised, lowered, or inclined. Upon tho metal 
10 standards F, F 1 , are binding screws, whereby 00111111010™ 1, 4, to nnd from tho 
source of electricity nre attached. The top E is provided with a central aperture, 
ur it mny bo annular, permitting the tidies c, e\ to pass through and below it while 
supporting tho globe. Upon tho base E is located a vessel mado of insulating 
material not affected by mercury divided into compartments D, D 1 , or two separate 
15 distinct vessols may be used. 

Tho tube 0 pusses into one D to near its bottom, while c passes into D 1 . A 
wire 2 connects II and F nnd a wire connects II 1 and F 1 . The parts boing placed 
in position, as shown in tho Figure, tho vessels D, II', are filled with morcury, 
mid the tube continuation of N, before mentioned, fastened to tho pumps. 

20 As tho air is exhausted from tho bulb the mercury rises in 0 and o'. During 
this operation care must bo takon that tile compartments D. D 1 aro kept suppliod 
with mercury and that upon the completion they are still full. Upon the proper 
degree of vacuum being attained the bulb is sealed at N and tho tube removed, 
At this stage tho mercury has risen to and remains at x, x, the hight at which 
25 atmospheric pressure sustains a column of mercury in vacuo, tho mercury contacting 
withe, e 1 , nnd passing a little distance above their ends. The columnsC,O', should 
he of such a diameter ns to give 110 greater resistance to the curront than does 
either of the conductors c, c 1 , 2 or 3. 

For high candle power incandescent lamps this arrangement makes a very 
30 mliuhle and durable seal, obviating any danger there may be of seal brenkngo 
arising from difference of expansion coefficient likely to cxi-t where a large metallic 
conductor is sealed directly to or in glass. For such reason in largo lamps this 
method may prove preferable to that of sealing direct. 

Hitherto in manufacturing the lamp the carbon having been prepared from 
35 paper, wood, or other suitable fiber, was placed ill tho lamp, whoso parts are then 
sealed; the lamp was then exhausted of air, a current being applied during the 
process of exhaustion heating tho carbon. 

l’rior to sealing in the lain]) and the process of exhausting tho completed lamp 
tho carbons were not heated, and prior to heating any defects therein could not be 
10 discovered. It is practically impossible to produce all the loops or slips of absolute 
uniformity or homogenity, or to carbonize all of them absolutely uniform throughout 
their entire mass. When heated to redness generally throughout their length somo 
show spots either less red or of a brighter rod than the average of the carbons, 
indicating for the first timo faults in tho carbons. Where there is a bad fault in 
*5 the carbon a white incandescenco appears, determining the life of the lamp and 
also affecting its resistance. Such lamps are unfit for use and tho entire cost of 
their manufacture has provod a loss. . 

It is now proposed to furnish a simple and cosy method and menus of testing the 
. carbons before tlioy are put in the lam]) proper, and so prevent defective or 
•id unsuitable carbons from boing embodied in completed lamps to be only thrown 
away upon discovery of tho faults, increasing, in fact, tho net cost of tho faultless 
ones. This is accomplished by a preliminary heating of tho carbons in vacuo, 
which by the following means can be cheaply, rapidly, and effectually done. What 
may bo culled a temporary lamp is formed of a globe or chamber of proper size, 
50 with an aperture at its top of a sizo sufficient to admit of the passage of a carbon 
ami its supporting base. Tho neck of tlm supporting base passes tightly through a 
soft niMww <»».!. S.1.1-1. :„i„ ti,„-n,«, ton of the adobe. The cork is so 


solt rubber cork which fits into the aperture iu top of the globe. 
























20 A.D. I860.—N 8 3765. '■*> 

Brewer's Impro vements in Electric La mps, X-c. _ 

sized tlmt its upper side is n little distance below tho top odgo of the aperti 
tlmt when the covk is in position a chamber is formed on top. On one aide 
well of the aperture is an opening having a tube upon its exterior, the n] 
being into the chamber referred to ns formed above tho cork. A mercury res 
is connected to tho opening by a flexible tube. IV hen tho cork is put into 
tho reservoir is elovutod ami tho mercury (lows thence, forming a seal ov 
cork; per contra, the reservoir being depressed, the mercury Hows back ill 
reservoir baring the cork. The globe is connected to a proper exhaust tube, s 
snrenoel drops being simultaneously used. By tins menus a carbon, may lie 
in the globe it sealed and exhausted quickly, and tho current applied testn 
carbon, which standing tho tost may ho placed in n permanent lamp. 

Suitable mechanism for carrying this part of tho Invention into ellect is she 
Fi". 35, which is a sectional view of tho preliminary proving or testing 
in'whic’h Fig. Q is tlio usual glass carbon support, which is sealed to the glass 
in the completed lamp at r. a is tho carbon to bo proved, secured thereto 
usual way. C is the temporary proving lamp, having nt its upper end an m 
sufficiently largo to admit tho carbon and its support, and provided with 
rubber cork B, through which tho neck of the carbon support Q passes 
cork B fits tightly in the aperture, the sealing being further rendered secur 
mercury seal E, a morcury reservoir il being elevated when necessary, so tli 
mercury therefrom (lows down through a tube c over the top of tho cork, 
the bottom of tho proving lamp C proceeds two two tubes, one n connecting 
JleLeod gage ; the other tube b leads to and connects with the vacuum npji 
In operation the carbon to be tested is placed in the proving chamber or 1. 
and the mouth hermetically scaled. Tho stop cock x in tube b is then c 
giving free communication between the chamber C and tho vacuum npp 
When tlie proper degree of exhaustion is attained circuit is closed through ca 
heating it to incandescence, causing defects if any to be visible. If the carbon 
defective it is discarded, the only loss being the labor and material, which art 
involved in tho manufacture of the carbon, and not as heretofore the lab 
materials, which weio ninny times greater, necessary to a completed lamp, 
evident that several carbons may be tested nt once in the proving clam 
temporary lamp. . . 

One of the objects in giving a very high resistance to the incandesce 
ductors used in said Edison’s system of lighting is to attain economy of n 
in tho conductors tlprefor. The resistance usually given them is sufficient 
desiicd economy in oidinnry thickly settled localities. For use however inS 
settled neighborhoods, as, say, the outskirts or suburbs of a town or city, it 
desirable to have a lamp by the use of which still greater economy o cinitli 
attained. In such localities, in order to lessen tho number of lights nei 
streets.it may also be desirable to have a lamp, in which the volume of 
increased, in order tlmt economy in the erection of lamp posts, etc., i 
subserved; and it may nlso be desirable to use lamps in which the volume i 
may be increased in oilier localities. As there is eventually a limit to the c 
life of tho carbon used, it seems desirable to so arrange a lamp that the o| 
life of tho lara]i may be prolonged beyond the average life of a carbon, to 
that tho cost of the labor expended in embodying a carbon in a lamp 
reduced. Both or cither of these results nre attained in tho lollowing 

An enclosing globe is used, made and put together in the usual .ntier. 

lamps herein described. To the inner and of one of tho conductors leading I 
lamp is fastened n double clamp, tlmt is, one tlmt is Y shaped, a carboi 
fastened to each limb of tho Y clamp. At tho other end each eai b< n is 
an individual clamp, each clump having its own conductor leading . ..t — 
lamp. The wires leading out of tho lamp and the wiros leading from a 
source of electricity are united at a circuit oontroling device, constructed si 
may close the circuit through either enrbon, tho circuit through tho ocher rei 
open; or it may close tho circuit through both, as carbons in a series; or 


Brewer's Improvements in Elcelrio Lamps, Ac. 

closo a circuit through each, the circuit through them being dorivod or multiple nro 
circuits. This part of tho Invention is moro clearly shown in Fig. 30, in whioli A 
is a "lass globe, and B tho supporting neck united nt a, b. Through tho nook B 
i,asses the conductors (i, 7, 8, which are scaled thorein. Upon tho innor terminal 
5 uf (j is the Y shaped clainp 15, in each leg of which is fixed a enrbon e or g. The 

other onds of these carbons nro in separate damps, e being fastened in the clamp <f 

of conductor 8, and g in clamp il 1 of conductor 7. Tho conductors C, 7, and 8 and 
tho circuit conductors 5, 9, are connected to a key E composed of metal contact 
i,dints 1, 2, 3, 4, and anvils x, s, s, as followsCircuit conductor fl is connected to 
10 point 1, contacting with *, and to anvil s, on which 2 contacts, while 9 is connected 
to anvil s with which both 3 and 4 may make contact. Conductor C is connected 
to anvil x; 7 to point 4, which contacts with 5 j and 8 to 2, which contacts 
with »; and to 3, which contacts with s. If points 1 and 3 bo put in contact 
with their anvils x, s, a circuit is formed, 5, via l, X, 0, D, e, d. 8, d, s, 
15 to 9, tho circuit through g being open. If 1 and 4 be closed on x 

and s the circuit is formed 5, via 0 D <J, 7, 4, a to 9, the circuit through e 

beiim open, and r/ alone in circuit and use. If 2 & 4 be closed on « andtho 
circint is from 5 via s 2, 8, c, D, g, 7, 4, s, to 9, and both e and g are in ono 
circuit that is in series ’ If 1 3, and 4, be closed on x, s, and s, tho circuit is 
20 from 5 via 1, x, 0, to" 15, where two paths aro formed, tho current consequently 
dividing one circuit being D, c, 8, 3,s, to 9, tho other D.fif, 7, 4, s, to 9, both carbons 
being in circuit, but each having its own circuit, which is a.derived one, so tinas 
the main circuit is concerned. When both aro used in multiplo nrc it s evident 
that tho net resistance of the circuit is one half tho resistance of ono, and a certain 
25 sized conductor is required. If both are used in series the resistance “ double tlmt 
of one and four times that of tho multiplo arc, in which enso tho conductor may be 
diminished tlireo fourths. As tho volume of light is that of twoi ordinaiy 1 amps 
is evident that a much less number may bo used with the same light giving result, 
l ffi's economy in luyin" main conductors and in the erection of lamps is secured. 
30 It is evident tlmt as one carbon only may be used nt a timc that iy so using one 

±k.“e ta i 

tilt’ j!Z“ e o? , °irSZ5n° l "fl” Whito cjw.ljm 

proper connections are made by enlarging key E on the principle* showa It is also 
evident that E may be provided with lover contacts instead of tho screw contacts 
used to explain tho principle of this Invention. • i lmrmnticallv in a 

In electric lamps formed by sealing an incandescing eond,.cto‘ ^ 

glass enclosing globe, there may bo danger sometimes that tle glass^and wire wn 
separate at the point where the conducting wires pass through and are sea^d into 

5 expansion of tho glass and wito uio , r m tnr>jiiulGscin<* material, 

herein aforementioned, owing to the high resistance of t p's been of “bio™; 
such small conductors nre used that tho danger r d to - d which 

the very least importance. It may bo des mabto. 1.°w<>»« - “ the neoessar y 

. reduce the danger to a ininimum, while aflortling at . V , • material Ono 

6 « support for the very small and delicate conductors, and nwriewiU ^ 

pa'rjof this Invention has for ^“et«ia.i the 

tit SSbSitsSS?. *i»«”» »'» “» lS 























22 




A.D. 1880.—N° 3765. 

Brewer's Improve ments in Eleotrio Lamps, <t-o. 

tho larccr enclosing globe, and sealed thereto at about the meridian lino of the 
smallM bulb. Tlio larger bulb is provided with a tubo by which it is attached to 
the air'exhausting apparatus, and where it is sealed after tho vacuum is produced 
Connected to this tube is a branch tubo leading from tho smaller bulb, so that both 
are sTmultaneously exhausted. This is shown in detail in Fig. 37, in which A is the 
glass enclosing globe formed with tho tube ft for attachment to the ex mus iag 
nnnaratus A small bulb B is made attached to the supporting nock C.and forrnod 

Fit 1 ss; 

IheHnes ^and thetube b conceded to the tubo «, the bulb B practically forming 
the seal to A. Tho tubo ft is then connected to tho exhaust apparatus. It is 
evident that a vacuum is created in both A and B. When a proper degree of 
exhaustion is reached tho tube b is scaled off at y, after which ^ ^ 

off at x, x. The vacuum in gloho A is thus protected by two sealings of each wire 
c e, and o', o», to only one set of which is there any danger, o» a', the other se , c, « 
from its distanco from tho heated portion of the lamp, nevor heating X 

be affected. As very small conductors are used it is nccessarry for sUb1t, a 
tliev be supported near the carbon, which is done at tho sordines , » 

of these *Z their proximity to the light is ever so heated as to, crackj it w.U stil 
subserve its functions as a support while the vacuum is presei ved by the se Us c, e, 
more distant from the clamps. Sometimes it may bo desirable to make H » 
which a less permanent seal is used, involving a less expensive methodI of seaimg, 
and which may be taken apart readily for the substitution of , 

purposes. This may be done as follows :_Upon a tube closed atoeedisup 
ported tho carbon, the conductors therefrom passing through the tl n “ d 
sealed hermetically in the top thereof. The enclosing globe is a 

somewhat larger than the tube, so that the carbon[ may b 0 P« sscd 1 ^ 3 

A robber packing is interposed between the outer walls of the tube and mnoiwaUa 
of the neck, securing the two together, the ends o the tube projecting beyond tho 
end of the neck. This projecting portion of the tube passes through be base 
rubber cup, the base of the neck resting upon the bottom of tho dcr " " t ™ f C F 
At the top Of the cop a rubber packing tills the space between the exte »r^ftlu 
neck and the interior of the cup. The space in the cup is filled minfwith 
which is retained in place in the cup by the packing last referred to, fernmng w h 
the rubber,, good seal for any temporary uses. Fig 38 shows a la np embody mg 
this portion of the Invention. A is the enclosing globe made with > long 1 ■ 
through which may bo passed the carbon B attached to clumps (j,, , • Q ^ 
conductors 1, 2, which arc sealed in the top of a tubo 0 lit c t c, t j u „]) 

somewhat smaller than the neck A 1 . Around tho base of C is a soft 
which fits into the lower part of the neck A, forming a tight join , cup 
two, supporting C and tho carbon in position in A and A; ^ 18 u . . o£ y 

through the bottom of which by a tight joint passes tho end of » .• u] y 

resting in the cup. At tho top of the cup a washer E of soft rubber fills tightly 

the spaco between A 1 nnd tho inner wall of the cup F, the space in P, t 

filled with mercury H or otlior suitable liquid, ilio lamp, so pu o „ 
exhausted, nnd tlien sealed nt ft in tlio usual manner, the combination of tlio I 
plugs or washers D and E, and tlio mercury H forming a reliable Beal. M 

Having thus described the Invention, what is claimed is hereby declared to 

First. An incandescing conductor formed of ono or more carbonized natural fibers, 

BU ScoonA* A carbon'elamp for uniting tlio incandescing and tho metallic conductors 
formed of a carbonizablo material, substantially as set forth. motors. 

Third. The method of uniting tlio incnndoscing and the metallic condu 5 
which consists in inserting both in clamps made of carbonizable matoria , 
carbonizing tho whole together, substantially ns sot forth. . D : M e, 

Fourth. Tho slip for enrbonization having enlarged ends formed in ou r 


A.D. 1880.—N° 3765. 23 


Brewer's Improvements in Electric Lamps, lie. _ 

and homogeneous therewith upon ono edge, or one side and ono edgo, tlio 
remaining edge and side being straight, substantially as set forth. 

Fifth. The method of forming a slip or filament for carbonization cons sting in 
securing a blank in damps or holders, having tlio configuration desired fot the 
5 carbon and shaving or cutting away tho superfluous mntorial, substantially as sot 

“’sixth A slip or filament for forming on carbonization the incandescing conductor 
of aii electric light made of hnst or fiber, liko cane and bamboo, substantially as 

10 “seventh A slip or filament for forming by carbonization the incandescing 
conductor of an electric light made of a material composed of fibres laying parallel 
through tlio length of tlio slip or filament, substantially as set forth. 

' Eighth. A slip or filament for carbonization provided with slots oi ''olcs m ts 
enlarged ends for holding it in the carbonizer and for passage of the clamping screws 

15 when nhiccd in a lump, substantially ns set forth. 

Ninth. Tho combination of tho shaving knife, tlio block C, and means for m g 
it, and tlio adjustable limiting screw, substantially as set forth. 

Tenth. The clamp formed of two portions, one being provtded wit'offsets or 
shoulders forming tlio bottom of slots acting as straight edges oi gages to tho slip 

* 5 «■$ 

stsj c sxu ,«. ... » 

30 ‘'“iWcciiih The hnrse-shoo with tliiekened or broadened ends for attachment to 

..W0MsSg^^S 

form, nnd carbonizing in such form, substantial y « ■ ^ electrie llimpa) consisting 

of 0 f 

Seventeenth. Tho metliod of forming c b Uock of w00 d into the shape 

«■»- “»»* 
portion of tlio broadened part,, substantial y ns t ^filamentary body with broadened 

. ..M-nSS - 

Nineteenth. The method of carbonizing 

lamps, uniform and regular in shape and . definite position relatively 

filaments while one or both ends are «« d m a ce « 00 ,Laoted the ends 
to the amount of contraction, so that wlion oarDom^eu 
50 slinll be in proper position to each ° tllor '. 3l ' b ^. b for incandescent eleotrio lnmps, 
Twentieth. The method of S' "^ s ^ nt strn ' m ’ and with 

consisting in maintaining the slips oi fila . ^ gtan ti a lly os sot forth. 

I onc er both ends fixed while,in process of c f , nn, Leant electric 


Twenty first. Tlio method of manufiiotiuang oarnons ior in yo9 w |,i c li 

as set forth, 





















A.D. 1880—N° 3765. 


Brewer's Improvements in Electric Lamps, <£•<;. 


Twenty second, The carbonizing pinto provided with a groove for shaping tho 
material, and a chamber or chambers permitting contraction during carbonization, 
substantially ns sot forth. • 

Twenty third. A carbonizing flask and tho plates thereof made of nickel, substan¬ 
tially as set forth. 5 

Twenty fourth. Tho carbonizing flask or box provided with groovos for the 
reeoption of the fiber, substantially as set forth. 

Twonty fifth. Tho carbonizing oven consisting of a case nnd a system of gas nnd 
air supply pipes combined, substantially as described and for tho purposes set 
forth. lb 

Twenty sixth. The combination of a caso or cover therefor provided with an 
inspection aperture and cover, moans for supplying gaseous fuel to the interior of 
the case, and means for mingling air under pressure with tho fuel, substantially as 
sot forth. 

Twenty seventh. Tho combination with one derived circuit of a multiple arc 15 
system of two or more lamps, each of a fractional resistance nnd radiating surface 
of the resistance and radiating surface of the standard lamp of tho system, tho 
fraction being the number used, substantially as set forth. 

Twenty eighth. The combination with one socket or holder nnd one derived 
circuit of one circuit controller, and two or more lamps each of a fractional 21) 
resistance and radiating surface of a standard lamp, substantially us set forth. 

Twenty ninth. Tho combination with the incandescing conductor of an electric 
lamp, of two fluid columns sustained by atmospheric pressure, mid forming both a 
part of the circuit and a liermetiea! seal to the lamp, substantially as set forth. 

Thirtieth. The combination with the incandescing conductor and the fluid 25 
columns of reservoirs connected to the source of electricity, and into which the 
columns dip for the maintenance of tho columns and the completion of the circuit 
therethrough, substantially ns set forth. 

Thirty first. Tho combination with an elect!ie lamp of the stand or support 
therefor, consisting of an insulating base and top connected by adjustable standards, SO 
substantially ns set forth. 

Thirty second. The combination with a globe or chamber of a much larger 
chamber or reservoir connected to air exhausting apparatus, which iminituins 
therein u high degreo of exhaustion, substantially 

Thirty third. The combination of a proving 
reservoir for sealing tho same, and exhaust resci 
exhnusting tho same, substantially' as set forth. 

Thirty fourth. Tho combination of a globe or chamber, a second and much larger 
globe, chamber, or reservoir, a valvod tube connecting them, means for maintaining 
a high degree of exhaustion in the larger reservoir or elm! iber and connected 4U 
thereto, and a gage for determining tho degree of exhaustion, substantially as set 
forth. 

Thirty fifth. The combination with the globe or chamber of a proving lamp, of a 
mercury reservoir connected to tho globe or chambor, so that tho stopper thorcot 
may at will bo covered or not covered by mercury, substantially as set forth. 

Thirty sixth. Tho method of testing carbons, consisting in subjecting them to the 
action of a current in a temporarily exhausted globe or receiver prior to their 
embodyment in completed lamps, substantially as sut forth. 

Thirty seventh. Tho combination in ono electric lamp of two or moro mean- ^ 
descing conductors, and means for connecting thorn in tho electric circuit, either in 
sorics or multiple arc, substantially as sot forth. 

Thirty eighth. Tho combination in ono electric lamp of two or moro incandescing 
conductors, and means for making or breaking an electric circuit through either ono 
ns may bo desired, substantially us set forth. . i • , 55 

Thirty ninth. Tho combination in ono electrio lamp of two or moro incandescing 
conductors, and menns for completing the circuit through oitlior, or through bothi 
substantially as sot forth, 


A.D. 1880.—N° 3765. 


Brewer's Improvements in Electric Lamps, £-c. 

Fortieth. Tho combination of contact points 1, 2, B, 4, anvils x, s, s, and circuit 
connections, substantially ns set forth. 

Forty first. In nn oloetric lamp, tho combination with tho enclosing globe or 
chamber of a second chambor through and into which the conducting wires puss 
5 and are sealed, botli chnmbors being hormotically sealed togother and exhausted, 
substantially ns set forth. 

Forty second. The method of sealing tho enclosing globe or chamber of an electrio 
lamp by sealing an auxiliary or secondary globo or chamber in tho opeuing of tho 
first or enclosing globe, substantially ns sot forth. 

10 Forty third. The mothod of preserving tho vacuum in the enclosing globo of an 
electric lamp, consisting in sealing the conducting wires at two points in a vacuum 
gloho hormotically sealed to the enclosing globo, substantially ns sot forth. 

Forty fourth. Tho combination with the neck of the enclosing globo and the 
carbon supporting tube of a cup containing a liquid receiving the end of the neck 
15 of the enclosing globo, and through which passes the carbon supporting tube, and 
washers or plugs tilling tho spaco between the neck and cup nnd the neck and tube, 
substantially as set forth. 

In witness whereof, I, tho said Edwnrd Griffith Browor, have hereunto set 
my hand and seal, this Fourteenth day of March, in tho year of our 
20 Lord One thousand eight hundred and eighty one. 

E. G. BREWER. (l.s.) 

































AJJ.1880. Sct. 16.W?-3285. 
BREWER’S SnsoncArroi 


FIG.31. 



















A.D. 1880, 2 ilh September. N° 3880. 


Systems of Conductors for the Distribution of Electricity, &c. 


LETTERS PATENT to Petei 
Middlesex, for an Invcntio 
fob the Distribution oi 


on, of 33, Chancery Lano, in the County of 
Improvements in Systems of Conductors 
3TRICITY AS A LlOUTINO AND MOTIVE POWER 


Agent, and Appliances connected therewith. A communication trom 
abroad by Thomas Alva Edison, of Menlo Park, in the State of Now Jersey, 
United States of America. 


PROVISIONAL SPECIFICATION left by the said Peter Jensen at the Offlco of 
tlio Commissioners of Patents on tlio 24th September 1880. 

Peter Jensen, or 33, Chancery Lane, in the County of Middlesex. “Impbove- 
ments in Systems of Conductors for the Distribution of Electricity as 
0 a Lighting and Motive Power Agent and Appliances connected there- 
WITH.” A communication from abroad by Thomas Alva Ed.son, of Menlo Park, 
in the Stato of New Jersey, United States of America. 

Where many translating devices converting electricity WJ? “tbor I 
are arranged upon the multiple arc or derived circuit s y st ,f“> ^^Sned n aU 
10 so far as possible an equal electro motive foreo or - pressure bo maintained in all 

Pi 'wh 0 /n t bow^ m eacli sot of conductors are rim out from the central stotion in a 
straight circuit contniuing a number of translating devices, P > t j 
, number of devices are in operation,' is apt to be g^test near^t the .central 
18 station, and to diminish gradually towards the end of the conductors, this drop 

’Sf'CSS' St irregulwity. 

20 energy as feeding conductors only, fcvL upon 

connected directly to the source, placing .the lamps or t a g 

[Price 6<L] 











2 A.D. 1880.—N» 3880. 

Jensen's Impts. in Systems of Conductors for the Distribution of Electricity, tie. 

service or lump circuits which connect to, and are fed hy, the feoding conductors, in 
such manner llrnt all tho lamp circuits are electrically distant substantially from 
tho sourco of electricity by tho same mass of conductor. By so doing tho greater 
portion, if not nil, the drop occurs in tho foeding conductors, tho pressure in tho 
sorvico or lamp circuits being practically uniform at all points. 5 

This Invention may bo carried into effect in several ways, of which tho following 
aro brief descriptions :— 

One method consists in placing upon tho conductors leading directly from tho 
central station or source of energy no lamps, using such conductors only ns feeding 
conductors to lamp circuit conductors, which they tap and feed into at their 10 
centres, such lamp circuit conductors being largest at their centres, and thcnco 
tapering to tho ends, tho lamps where many arc to bo used being placed in circuits 
derived from these lamp circuit conductors only. 

From a central station several sets of feeding conductors may lead out, each 
foeding into its own set of lamp circuit conductors. 15 

When it is desired to use a few lamps near tho central station, they may bo 
placed upon a direct circuit therefrom with rcsistanco at tho commencement or 
home end of tho circuit, suflicicnt to then reduce tho electro motivo force of such 
circuit, so tlint it shall only bo equal to that in tho inoro distant circuits, and ono 
or more of such circuits may be combined with tho circuits beforo described. 20 

When largo buildings or blocks of buildings using many lamps aro to bo supplied, 
it may bo desirable to lay therefor separato feeders insulated from each otlior. 

While in this system it is preferred to uso round metallic circuits, it is evident 
that by the introduction of propor grounds tho earth may bo used as half of the 
circuit. 25 

It may be desirable in using round metallic circuits to add grounds ns an aid to 
half the circuit, in which ease such half the circuit may be of smaller conductors, 
provided its size he such that its resistance, ndded to that of tho ground circuit, 
shall not exceed that of tho other half of tho circuit. 

Where several central stations are used in a city, each having feeding conductors 30 
lending to lamp circuit conductoi-s, of tho description beforo noted, it may he 
advisable to connect tho feeding circuits of all the stations, equalizing tho electro 
motive force or pressure throughout the entire system of tho plnce where the 
central stations aro located. 

Another method consists in laying tho service conductor in squares around a 35 
central station, the sets of service conductors (positive and negative) in each set 
being concentric to each other, so to speak, feeding circuits leading to and 
connecting with each sorvico set nt several points. 

Tho service sets may also be connected togothor at sovcrnl points so ns to aid 
in equalizing tho pressure throughout tho entire system. ™ 

In another method two conductors forming a complete metallic circuit aro laid 
entirely around each square or block ns tho scrvico conductors of such block. 
Feeding conductors from the sourco of electricity lead to and connect with tho 
service conductors, but upon opposite sides, that is, ono conductor, say, tho one 
from tho + polo connects nt some point to ono Rorvico conductor of a block, wliilo « 
tho ono from tho — polo connects to tho other service conductor nt a point 
exactly opposito to tho other, so that tho terminals of nil house circuits of a block 
or tho points where tho houso circuits connect to tho service conductors, are alt 
equidistant from tho sourco, or that tho same mass of conductor intervenes. 

A series of blocks may bo so arranged, tho feeding conductors leading to the 
extremo or opposite blocks, ono to each of tho series, tho service conductors ot the 
Mocks being united by cross conductors, so that ouch blook is distant electrically 
from tho source by the siuno mass of conductor. , . 

Where a conductor varying in size throughout its length is used, it is P rc ' , 
ferable to mako it a compound ono, composed of several single wires of different 
lengths, one or two of which extend tho whole length of tho conductor, others 


spa*!,. A.D. 1880.—N° 3880. 3 

Jensen's Impts, in Systems of Conductors for the Distribution of Electricity, <£u 

ending at various points. Those wires aro not insulated, but merely grouped in a 
bunch, which linvo transvorso fastenings at intervals, or which may bo fastoned 
together by branch conductors pnssing around whore connections aro formod. 

It is preferable to form all conductors which vary in sizo decreasing from some 
5 point in this manner, and it is to be understood in those descriptions that all such 
conductors aro so made. 

This system also contemplates tho supply of electricity for both light and power. 
It is proposed that tho current used for these purposes should bo paid for at 
different rates, therefore where both powor and light are desired two branch 
10 circuits are run from tho mains into tho houso or locality of translation, ono for 
the lights and ono for tho engines, a meter being placed in each. 





ppirlflcnilon. 


Jensen's Iinpta ♦ in Systems of Conductors for the Distribution of Electricity, fa. 


SPECIFICATION in pursuance of tlio conditions of tho Letters Patent filed by 
tlio said Peter Jonson in tho Groat' Seal Patent Office on tho 24th March 
1881. 

Peter Jensen, of 33, Chancery Lane, in tho County of Middlesex. “Imfrove- 
ments in Systems of Conductors for the Distribution of Electricity as 5 
a Ligutino and Motive Power Agent and Appliances connected there¬ 
with." A communication from abrond by Thomas Alva Edison, of Menlo Park, 
in tho State of Now Jorsoy, United States of America. 

Where many translating dovicos for converting electricity into cither power or 
light are arranged upon tho multiple are or derived circuit system, it is essential 10 
that, so far as possiblo, an equal olectro-motivo forco or “ pressure ” bo maintained 
in all parts of tho system. 

When however each set of conductors are run out from tho central station in a 
straight circuit containing a number of translating dovicos, the pressure when a 
number of dovices nro in operation is apt to bo greatest nearest tho central station, 15 
and to diminish gradually townrd tho end of tho conductors, this “ drop ” being duo 
to the resistance of tho main conductors. 

The object of this Invention is to obviate such irregularity and to maintain 
practically throughout tho ontiro system an equal pressure. 

This is accomplished by using tho conductors leading directly from the sourco of 20 
energy ns feeding conductors only, placing no lamps ordinarily in tho circuit 
connected directly to tho Bourco. placing tho lamps or translating devices upon 
servico or lamp circuits, which connect to and are fed by the feeding conductors in 
such manner that all tho lamp circuits are electrically distant substantially from 
tho source of electricity by tho same mass of conductor. By so doing tho greater 25 
portion, if not all, tho drop occurs in tho feeding conductors, tho pressure in tho 
servico or lamp circuits being practically uniform nt all points. 

This Invention may bo carried into effect in sovcral ways, of which the following 
are brief descriptions :— 

One method consists'in placing upon the conductors leading directly from the 30 
central station or sourco of cnorgy no lamps, using such conductors only as feeding 
conductors to lamp circuit conductors, which they tnp and feed into at their centers, 
such lamp circuit conductors being largest nt their centers, and thcnco tapering to 
the ends, tlio lamps where many are to bo used being placed in circuits derived 
from these lamp circuit conductors only. 05 

From a central station several sets of feeding conductors may load out, each 
feeding into its own set of lamp circuit conductors. 

Where it is desired to uso a few lamps near tho control station they may bo 
placed upon a direct circuit therefrom with resistance at tho commeucoment or 
home end of tho circuit, sufficient to then reduce tho electro motivo force of such *# 
circuit so that it shall only bo equal to that in tho more distant circuits, and ouo or 
more of such circuits may bo combined with tho circuits boforo described. 

When largo buildings or blocks of buildings using many lamps are to bo 
supplied it may bo desirable to lay therefor separate foedors insulated from each ^ 

While in this system it is preferred to uso round metallic circuits, it is ovident 
thnt by tho introduction of propor grounds the earth may bo used as half of tho 
circuit. 

It may bo desirable in using round motallic circuits to add grounds as an aid to 
half the circuit, in which case such half tho circuit may bo of smaller conductors, 
provided its size bo such thnt its resistance added to that of tho ground circuit 
shall not exceed that of tho other half of tho circuit. 


Jensen’s Impts. i n Sy st ems of Conduc tors for the Distribution of Electricity, Jo. 

Where soveral control stations aro used in a city, onch having feeding conductors 
leading to lamp circuit conductors of tho description boforo notod.it may bo advisablo 
to connect tho feeding circuits of all tho stations, cqualizing'tho electro motivo forco 
or pressure throughout tho ontiro system of tho placo where tho central stations 
5 nro located. 

Another method consists in laying tho servico conductor in squares around a 
central station,_ tho sots of service conductors (positive and negativo in each set) 
being concentric to onch other so to speak, feeding circuits loading to and connecting 
with each service sot at soveral points. Tho servico sets may also be connected 
0 together nt several points so ns to nid in equalizing the pressure throughout the 
entire system. 

In another mothod two conductors forming a complete metallic circuit are laid 
entirely around each square or block as the servico conductors of such block. 
Feeding conductors from tho sourco of electricity lead to and connect with tho 
5 servico conductors, but upon opposite sides, that is, ono conductor, say tho one 
from tho polo connects nt some point to ono servico conductor of a block, while 
the one from tho — pole connects to tho other service conductor at a point exactly 
opposite to tho other, so that tho terminals of all house circuits of a block, or tho 
points where the house circuits connect to tho servico conductors, aro all equidistant 
III from tlio source, or that tho same mass of conductor intervenes. 

A series of blocks may be so arranged, the feeding conductors leading to tho 
exlremo or opposite block, ono to each of tho series, the service conductors of the 
blocks being united by cross conductors, so that each block is distant electrically 


from tho source by the same mn 
5 Where a conductor varying ii 

to make it a compound one, co:..,.- - „ _ 

one or two of which extend thu whole length of tho conductor, others ending at 
various points. These wires are not insulated but merely grouped in a bunch, 
which lmvo transverso fastenings at intervals; or which may bo fastened together 
U by branch conductors passing around where connections aro formed. 

It is preferable to form all conductors which vary in size decreasing from some 
point in this manner, and it is to bo understood in these descriptions that all such 
conductors aro so made. . . . 

This system also contemplates the supply of electricity lor both light and 

P Tis proposed that the current used for these purposes should bo paid for at 
different rates. Therefore where both power and light are desired two branch 
circuits run from tho mains into the house or locality of translation, ono for the 
lights and ono for tho engines, a meter being placed m each. . . 

0 The foregoing may bo better understood by a reference to the Drawiugs, in 
which aro given diagrammatic representations of circuits, in which— 

Fig. 1 illustrates a plan wherein the conductors nro made larger at their home 

ends, gradually tapering to tho outer end ol tho system. _ , 

When such plan is used, it is preferable to make each conductor acompeundon 
5 composed of several single wires of different lengths, one or twofwiccxtend 
the whole length of tho conductor, others ending at various ipo nts, as shown in 
Figure lb. These wires aro not insulated but merely grouped ! ^ 
have transverse fastenings at intervals, or which may bo “ ul ^ 
branch conductors passing around where connections nro loimcd, 

. CO tF?2Tedi,,g conductors 1, 2, lead from control station c 
3 the lamp circuit 3, 4, at about its center, the conductors of tlio h mp c cm 
largest at that point, and also larger capacity at that point than the 
conductors. 


is of conductor. 

size throughout its length is used, it is preferablo 
nposed cf several single wires of different lengths, 







0 A.D. 1880.—N° 3880. , WC i»„u M 

Jensen '« Impts. in Systems of Omullectors for the Distribution of Electricity, &c. 


By tliia nrmngoinoiil most, of tho fall of pressure or " drop ” takes place in the 
feeding circuit, so that it cannot afl’cot any lumps, whilo tho “ drop ” in the lamp 
circuit is reduced very low, the 11 drop ’’ from tho center of tho lamp circuit to 
either terminal being only about one fourth what the drop would he from y to :, 
if either end were connected directly to tho central station. 5 

Any desired number of lamp circuits may be so arranged, each having its proper 
feeding conductors, two so arranged being shown in Figure !1. 

In some instances, when it is desired to use a few lumps near the station, tlioy 
may bo placed directly upon main conductors and combined with tho circuit,shown 
in Figures 2 and !!, as shown in Fig. -1, whero feeders 5, G, connect with 10 
lump circuit 0, 10, arranged as in Figures 2 and 3, while circuit 1, 2, connected 
directly to c, s, has a few lamps upon it, in which ense a resistance should ho used 
therein to lessen the electro motive forco in 1, 2, to the samo extent as it is lessened 
by tho longer eonductom 5, 0, 

With such arrangement may also bo combined an ordinary terminal circuit 15 
containing a few lamps, such as tho circuit 13, Id, in Fig. 5. 

In Figure 0 is shown direct or main feoding circuits 1, 2, and 5, G, with lamp 
circuits 3, 1, and !), 10, with branch feeders 7, S, IS, 1G, and 21, 22, lending into 
side streets supplying lamp circuits 17, 18, 1!), 20, 23, 21, and 25, 20, tho branch 
feeders being derived circuits from the main feeders, all constituting a multiplo arc 20 
system. In Figure 7 feeding mains 1, 2, connect to the center of tho lamp 
circuit 3, 4, while feeders 5, 0, leading to a greater distnuco and to a circuit 
whero comparatively few lamps are required, connects to the end of lamp 
circuit 9, 10, whose conductors gradually taper from tho point of connection. This 
arrangement is sometimes desirable in sparsely settled localities as involving 25 
economy in the laying of conductors. 


In figure 8 is shown feeding conductors 1, 2, from which lead house feeders a,b, 
which connect to lamp circuit b', which are of same description as circuits 3, 4, 
Figure 2. Figure 9 shows a series of houses or buildings c, d, c,f, to each of which 
leads ft feeding circuit of insulated conductor, tho lamp circuit of each house being 31 
thereby put in direct connection with the central station c, s, the electro motive 
force of any one lamp circuit not being affected by the others. In Figure 10 are 
two blocks of buildings A, B, composed each of several houses h,h,h, separate 
feeding circuits 1, 2, and 3, 4, leading to branch feeding circuits from winch lamp 
circuits lead into each house, each house or lamp circuit being provided with its 3t 
own connection and motor. In tho arrangement shown in Figures 8, 9, 10, the 
greater portion of the fall or drop occurs in tho conductors leading to tlio liouso or 
block lamp circuits, tho forco or pressure in tho branches leading into tho houses 
being maintained practically uniform thereby in each lamp circuit. In Figure 11 
is illustrated the substitution of ground O, G, for one conductor, say 2 of Figuro 1, 
of tho feeding conductors, a common ground being provided for nil tho lamp3 in one 
houso lamp circuit. 

In Figure 12 is shown a comploto metallic feeding circuit 1, 2, in which grounds 
G, G, are ndded ns auxiliary to tho portion 2 of tho circuit. 

While ordinarily a metallic circuit is to bo propnrod, by adding grounds ono 45 
portion of the circuit may bo of smaller conducting capacity, tliuh tending to 
economy of conductor; caro should bo taken that tho capacity of 2, however, is such 
that its resistance and that of tho grounds bo not greater than that of tho portion 1 
ol tho circuit. 

In Figure 13 is shown a serins of central stations c, s, from cncli of which lead 50 
main feeding circuits M (which may bo of any desired number), each connecting to 
and feeding into a lamp circuit l, c. 

The mains of all tho stations are connected by conductors n, n, n, so that all the 
stations are electrically connected into one general system, whereby the pressure 
throughout the entiro system is equalized. , Jl 

In Figuro 14 a houso circuit s branches from the main circuit 1, 2, tho circuit S 
branching into two circuits, on ono of which all the lumps aro placed, the other 


gprdflfntlon. 


1 


A.D. 1880.—N° 3880. 

J ensen's Impts. in Systems of Conductors for the D istribution of Electricity, die. 

being a motor circuit only, as shown, in each of which meters aro placed, so that 
tho amount of current used for each purposo may be determined. In Figuro 15 tho 
lamp circuit L, C, is. fed by n number of feeding circuits, connecting thoroto on 
opposite sides alternately 1, 2, 3, 4, mid 5, 0, forming tlirco feeding circuits, by 
5 which arrangement a comparatively uniform forco or pressure may bo maintained 
throughout tho entiro system. Figures 1G and 17 illustrate the method of laying 
the service conductors around blocks with foedine conductors leading thereto from 
the central station. C, S, is the central station, around which following tho 
general direction of tho blocks or squares of tho locality aro laid tho sots of 
10 conductors 1, 2, .3, etc,, so that they are, so to speak, concentric with each other. 

' From the central station branch conductors lead to each of tho main sets 1, 2, 3, at 
a numbor of points, for instance a, a', lead to sot 3 ; b, b l , to 2; c, o', to 1. In 
Figuro 10 eight sets of branch conductors aro shown leading to each of tho main 


15 In Figuro 17 two sets of main conductors 1, 2 are shown connected to tho main 
station by four sets each of branch conductors b, b', c, o', differing bowover from 
Figure 1 in that the main sets 1, 2, are connected together by numerous sets of 
coupling conductors d, <Z*. 

As proceeding from the central station each set of main conductors traverses a 
20 larger area of territory, and has a larger amount of work to do, if all the conductors 
were of the samo size there would be increased resistance. It is desirable bowover 
that each (no lamps on branch conductors or couplers) set should bo of the samo 
resistance, and that tho same ratio of resistance of conductors to translating devices 
should exist in all the sets. This is accomplished by increasing tho size of the 
25 conductors as they aro laid further away from the central station. 

Having determined the relative resistance wliich should exist between the 
resistance of the conductors and that of the sum of the translating devices most 
profitably to boused with such conductors, the increase of size to bo given is 
that which shall preserve such ratio, taking into consideration the increased length 


30 of conductors and tho increased number of devices to bo probably supplied thereby, 
liy this method of laying and uniting the conductors an equal pressure or electro 
motive force may bo maintained throughout an entire system. Figures 18, 19, 20, 
and 21 illustrate modifications of the last described system, which may bo called 
tho block or square system. In these Figures A is a central station, at which is 
35 located a suitable source of electricity, and from which lead feeding conductors 1,2; 
11 represents a block or square, around which are laid tho scrvico conductors 3, 4. 
Conductor 1 leads to 3 at l, upon ono side of the block, while 2 leads to 4 at 4, 
upon tho opposite side of the block. The greater portion ot any fall of electro¬ 
motive l'orco will occur in conductors 1, 2, while it will be constant at all pom s in 
40 the scrvico conductors 3, 4, because every point in such conductors is distant horn 
the source by exactly the game muss of conductor, us is evident irom inspection ot 
tho diagram. , 

In Figuro 19 two blocks B arc shown, conductor Heading to and connecting 
with 3 of block Bj while 2 leads to and connects with 4 ot B, B; while cross 
45 conductors 5, G connect with; tho conductors of tho blocks. In figure 20 torn 
blocks aro shown, conductor 2 being connected to 4 o tlio right hand blocks 
through a branch 9 leading to both right hand blocks, wl.de l connects direct j to 
both loft band blocks. In this Figure is shown a house circnil. a, a, contaimns 
lamps, indicated by circles placed between a, a, lit i , 

50 connected as in Fig. 10, while from the cross conductors o, G, lends. . de IV ®“ 
circuit 7, 3, leading to two other blocks arranged ns described. Ins ea l o t o 
blocks, as in Fig. 19, any number may be used, in all these plans e,nil Mock: uud 
ouch houso circuit arc electrically equidistant from the source, by wluc i ..lot mty 

ami equality therein ia attained, tho loss or drop ol iorco occurnng g 


What is claimed is,— . , a, ... 

First. The method of equalizing the pressure or electro motive toicc tin .u, .out 






A.D. 1880.—N° 3880. 


. Specification, 


Jcimcn'a Jmpts. in Systems of Conductors for the Distribution o f Electricity, dc. 

an elcctrio distributive and translation system, consisting in usin« feodum circuits 
winch connect to and food into circuits on wliich are arranged (ho transktinc 
devices, substantially ns sot forth. ° 

Second. Thp combination with a circuit containing translating dovices of n 
a fooding circuit loading thereto from the source of enorgy and coiitninine no 5 
translating devices, substantially as sot forth. 

Third. The combination in ono systom of a main circuit connected directly to a 
source of energy and containing translating dovices, and providod with means for 
lessening its forco or pressure to tlmt of tho average of the system, a circuit not 
directly connected to the source of energy containing translating devices, and n 10 
leeding circuit connecting the lattor circuit with tho source of enorgy, substantially 
as sot forth. J 

Fourth. The method of equalizing tho pressure or electro motivo force in tho 
lamp or translating circuits, by connecting the same to tho source of energy by 
feeding circuits in which occur the greater percentage of fall of forco, substantially 15 
as set forth. J 

Fifth. The combination of a number of insulated wires or different lengths 
grouped together and fastened at intervals, forming a gradually tapering conductor, 
substantially as set forth. 1 ° 

Sixth. Tho combination with ono dcrivod circuit of two branch circuits for 20 
different classes of translating dovices, each containing n motor nnd a feeding 
circuit, substantially as sot forth. 

Seventh, lhe combination with one lnmp circuit of a sories of feeding circuits, 
substantially as sot forth. 

Eighth, file combination with ono sido of an entire metallic circuit of a series 25 
of ground connections as auxiliary thereto, whereby a lessor conductor may be 
used m such half, substantially as set forth. 

Ninth. The method of laying the conductors in an electrical supply system, 
consisting in laying them in sets concentrically as explained, each set being 
connected to tho central station at several points, substantially as sot forth. 30 

Tenth. Tho mothod of laying tho conductors in an electrical supply system, 
consisting in laying thorn in sots concentrically as explained, each sot being 
connected to the central station by several sets of branch conductors, nnd tho 
various sots bo...g connected to each otlior by several sots of coupler conductor.'.; 
substantially as set forth. 35 

Eleventh. As an improvement in tho art of distributing eloctricity for uso 
ns a lighting and motive powor ngont, tho method of laying tho conductors, 
consisting in laying around each block tho service conductors, and uniting the 
same to tho sourco of electricity by feeding conductors arranged as sot forth, all 
substantially ns herein shown nnd described. 10 

.twelfth. As an improvement in tho art of distributing olectncity for uso as a 
lighting nnd motive power agent, tho system of conductors set forth, consisting of 
service conductors laid around each block, feeding conductors connecting thorn to 
the sourco of electricity nnd united to them at tho points designated, and cross 
conductors connecting tho service conductors of a series of blocks, substantially as 15 
set forth. 

In witness whereof, I, the said Peter Jensen, have hereunto sot my hand 
and seal, this Twentysoeond day of March, in tho year of our Lord One 
thousand eight hundred nnd eighty ono. 

PETER JENSEN, (la) 50 

1‘riutcra to tliu Quran's most Excellent Majesty. 

For llcr Majestys Stationery Office. 









































A.D. 1880, 25 tk September. N° 3894. 


Elootro-magnetic Railroads, &o. 


LETTERS PATENT to Peter Jensen, of 33, Chancery Lnne, in the County of 
Middlesex, for an Invention of “ Improvements in the Construction of 
Machinery and Appliances for Electro-maonetic Railroads, and in 
the Generation, Distrirution, and Translation of Electricity for 
Working the same.” A communication from abroad by Thomas Alva 
Edison, of Menlo Park, in the State of New Jersey, United States of 
America. 


PROVISIONAL SPECIFICATION left by tho said Peter Jenson at the Office 
of the Commissioners'of Patonts on the 25th September 1880. 

Peter Jensen, of 33, Chancery Lano, in tho County of Middlesex. “ Improve- ■ 
ments in the Construction of Machinery and Appliances for. Electro¬ 
magnetic Railroads, and in the Generation, Distribution, and Translation 
of Electricity for Working the same.” A communication from abroad by 
Thomas Alva Edison, of Menlo Park, in the Stato of New Jersey, United States 
of America. 

Tho object of this Invention is to furnish an economical and reliable system of 
\ 10 electro magnetic railways or tramways, which while useful in any locality shall 
be particularly adapted in regions where tho traffic is too light for ordinary steam 
railways, or whero tho main bulk of the traffic is limited to certain seasons, 
or where the difficulties or expense of grading render ordinary steam roads 
impracticable. 

15 To this end the Invention consists in a complote oloctro magnetic railway system 
embracing tho generation, distribution, and utilization of electric currents as a 


embracing tho generation, distribution, and utilization of electric currents as a 
motive power, and in tho novel device nod combination of devices therefore, as 
moro particularly hereinafter described and claimed. 

In carrying this Invention into effect the rails of tho track are electrically con- 
20 nectcd, so that each lino of rails forms ono half of a circuit. Tho road is divided 
into sections, whero from its length this is desirable, each scotion forming sub3tan- 
\Priac Is. 0A] f 









2 A.D. 1880.—N° 8804 /wu-tai 

SlwIBnUon. 

_ ■ Jenson's Improvements in Electro-magnetic Railro ads, £c. 

tially a small independent rnilroad. For each section n contral station is providod 
nt winch is ocated any suitable motor for giving motion to ono or moro mumiota 
or dynamo electric machines connected thereto. ° 

At each contral station, and also at other points whoro necessary, a portion of a 
section is electrically out off from the remainder, which in connection with a sidin» s 
thore lmd enables trains to pass each othor. Movable switches or shunts aro formed 
in tho onds of tho main track adjacent to tho sidings. The switches are operatod 
by mcchnmsm set in motion by electro mngnotic motors having connection to tho 
central station. From eacli end of each rail section connections are mado to scries 
of electrical switches at tho central station, by which menus the engineer there in in 
chargo is enabled to put tho current off or on, or reverse the same or any particular 
track or switch section, and to opernto any particular switch. 

For tho travelling motor or locomotivo an electro magnetic engine is mounted 
upon a suitablo frame supported upon the axles of tho driving nnd other wheels 
In order that the circuit from ono lino of rails to tho other be not directly through IS 
tho wheels and axles, but bo through the motor, each car is, so to speak, electrically 
. cut in two by tho interposition of insulating material somowhero in its structure 
the poles of the motor being connected ono to each division. A seemingly preferablo 
method is to form the hub and flange of a wheel of separate metallic parts, uniting 
them by bolting each to a wooden web, which insulates tho two, whereby tho «0 
body of the car and tho axles nro insulated from tho track. 

Contact springs benr ngainst tho flanges, or preferably against hubs secured 
thereto by cross bars or “ spiders," whoso outer ends nro bolted to tho flanges. 
These contact springs nre connected to tho commutator springs of tho motor, ono to 
each respectively, through the reversor nnd govornor, controlled contacts hereinafter 25 
spoken of. 

As in a central systom the motivo power is constant, irrespective of the con¬ 
ditions of the trains, it seems requisite that the motive power should bo connected 
directly and inflexibly to the driving wheels, but in some sueh manner os will enable 
the force to be gradually applied to or withdrawn therefrom. 30 

Therefore n friction wheel is mounted upon a shaft of the motor, nnd ono upon 
the main driving axle, tho two being disconnected, so that motion is not cointnuni- 
cated from ono to the other. In a swinging frame pivotted at one end, nnd provided 
atlho other end with a handle, is mounted another or connecting friction wheel, 
which on depression shall take upon both the friction wlieols before nnmed, and 35 
transfer the force from ono to the other; of course tho nmount of this transferring 
is dependent upon the perfection of tho frictional bearing of tho intermediate upon 
tho other two friction wheels, and may bo varied between tho limits of the minimum 
and maximum frictional contact. 

To accomplish tho same result a motor pulley- and a driving pulley may bo con- 40 
nected by a loose belt to bo tightened by a swinging pulley belt tightener, or the 
same result may bo accomplished in soveral other known ways. 

As tho motive power sufficient to inovo a load upon a bovil with great speed is 
totally inadequate to move it with tho samo Bpeed up an incline, nnd ofton fails to 
move the load at all, means (oxtra amount of steam generative capacity for example) +5 
are generally used for furnishing a large excess of power over tho amount usually 
required, adding largely to the dead weight to bo carried. In this system however 
it is proposed to use at all times for a load or train only tho amount of powor 
normally required under favorable conditions, providing means by which speed is 
automatically exchanged for power when necessarily, this to bo accomplished by a 50 
governor, which upon speed falling upon reaching an incline shall automatically 
operate to alter tho leverage either of bolts, friction gear, or dutches, through which 
tho motor acts upon the driving whcol. 

As tho devices for this purposo are applicable to other than olectro motor systems _ 
they are not further heroin described, but will form tho subject mattor of a separate 
application for a Patent. 


erKiiicaiioti. A.D. 1880.—N° 3894 3 

_ Jenten’a Improvements in Elcclro-magnctic R ailroads, £c. ' 

»J J ESLr i ti iS 1 ® cnto<1 1 a reversing key through which the circuit passes to 
tho motor, which may be used ns a brake in case of emergency, tho reversing of 
the current acting to reverse tho direction of tho motor, and thereby more rapidly 
stop it. The operative lever of this reversor is so combined with a spring that it 
5 may bo hold in a central position without any of its contacts infringing on othor 
contacts, and so act a.so os mere circuit closer .or breaker. A centrifugal governor 
driven trom the driving axlo is usod connected to a series of contacts so as to break 
the circuit at a number of points simultaneously upon a certain predetermined 
speed botng reached. 

10 Provision is made to dispenso with the necessity of much grading, enabling the 
engmo to ascend ordinarily impracticable grades, as follows:— 

Upon one or bpth Bides of tho engine car a wheel having a grooved face adapted 
to clasp tho head of tho rail is mounted in a hearing so combined with a screw or 
other lilting dovico that it may bo depressed into or elevated from contact with tho 
15 rail. Upon its axle is fixed a rag or sprocket wheel. 

Upon the main driving axle is loosely mounted a friction wheel having attached 
to it a rag or sprocket pinion. To this loose wheel when necessary motion is com¬ 
municated from a friction wheel on tho motor shaft through an intermediate 
friction wheel mounted in a swinging frame, ns before described. A sprocket 
20 chain connects tho sprocket wheel on tho nxlo of the grooved wheel and tho sprocket 
pinion. Under ordinary circumstances this Iriction wheel in the main axle has no 
motion communicated to it, and tho grooved wheel is not in contact with the 
track; when neccssaiy the grooved wheel is depressed nnd tho intermediate 
friction wheel so applied ns to cause the loose wheel on tho main driving axle with 
25 its rag or sprocket pinion to be rotated, the motion being communicated to tho 
grooved whool, which grasping and biting upon the rail head pulls tho load up 
without danger of slipping. 

Where the rails aro used as conductors of an electrical circuit there is always 
moro or less surfneo conduction, tho nmount depending largely upon tho dampness 
30 or dryness of the adjacent soil ties, and such like. 

Tliis surfuco conduction may bo largely reduced, or prevented entirely, in tho 
following manner:— 

Botwcen the rail nnd the tio is placed a pieco of felt, papormache, or other flexiblo 
insulating material, preferably so treated ns to mnko it water proof, which piece 
35 extends upward on tho web on both sides of tho rail to tho head, forming an 
insulating shoo. 

Between it and the spike is placed apiece of inotal of tho general configuration 
of tho foot of tho rail, upon which the head of tho Spike takes and bears, so that 
the insulating material is protected from abrasion or damage by the spike. 

40 Instead of tliis metal piece a much heavier piece of wood may be used, forming a 

shoe fastenod down by tho spike and in turn securing the rail. 

The foot nnd web of the mils aro covered with some elastic insulating 
composition; for example, a rubber paint of which tho baso is pure linseed oil, tho 
tics, for a spnee of, say, one half foot to a foot, on each sido of the mils being 
*5 similarly painted. , , „ . . „ 

In using electro motors tho best results nro obtained when tho speed of tho 
rotating armature is maintained uniform and at a very high rate. 

In railway motors a large excess of power over that required for a given speed 
upon tho level is providod/in order that oven a very much diminished speed may 
50 be maintained upon an up grade, the speed of tho motor being diminished 

^Onoobjrefof this Invention is to so arrango a motor in relation to the driven 
mechanism that tho speed of tho motor shall always remain unchanged, not being 
affected by changes in the speed of the driven mechanism, and that po»ei may bo 
«6 exchanged for speed, or vice versa, as circumstances may demand, will out the 
speed of tho motor being affected. Another object is to furnish a method 'll pio- 


_ Jensen's Improvements in Electro-ma gnetic Railroads, <l-c. 

pulsion of trains analogous to tho action of a quadruped in drawing a load, especially 
applicable as moans for climbing a grade or assisting therein. 1 

To accomplish these objects a thread is mounted upon the shaft of tho rotating 
armature meshing into n worm upon a shaft, at whoso opposito ond is a bevil 
gear taking into a bevil gear upon a shaft parallel to the shaft of tho ongino. 5 

Upon this latter shaft are two gear wheels, ono having several times as many 
teeth as tho other, both being loosely mounted upon a slinft, on which nud between 
tho two gears is fixed a suitablo clutch in order that ono or the other may bo 
caused to rotato with tho nxlo upon tho clutch being thrown to tho oxtreme limit 
or its motion, but that when the clutch is in an intormediato position neither shall 10 
bo locked into tho shaft. In order to prevent tho clutch being moved too rapidly 
it may bo operated by a screw threaded lover passing through tho free end of the 
lovor. 

Upon the main driven axle two gear wheels aro rigidly fixed, ono large and one 
small, tho larger ono gearing with the smaller ono loose upon tho shaft last noted, 15 
while the smaller ono gears with tho larger one loose upon Buck shaft. 

It is evident then that whether speed bo converted into power or power iuto 
speed will depend on whether motion be communicated from the shaft driven from 
tho armature shaft to tho main driven nxlo through tho sumllor or through the 
larger gear thereon. 20 

For use upon grades a device which may be called a creeper is used somewhat as 
follows:— 

Upon the front of tho engine is mounted a vertical shaft carrying a worm gearing 
into tho thread upon the armature shall. 

This vertical shaft is mounted in adjustable bearings, so that tho worm may bo 25 
thrown into or out of gear with tho thread, as desired. 

Upon the lower end of tho vertical shaft is a bevil gear meshing into a bevil 
gear upon a horizontal shaft, to whose ends by crank arms or pins are attached 
rods, each carrying at its opposito end a box or casing provided with n central 
wheel which rides upon the rail. In tho box or casing, so as to take upon tho sides 30 
of tho rail, are eccentrically pivoted two wheels, one on each side. These side 
wheels being eccentrically pivoted allow tho box to bo pushed forward along tho 
side of tho rail, but prevent retrograde motion by closing together and grasping 
tho rail. Tho arms carrying tho grippers or creepers aro mounted so that they 
may be let down upon or removed from tho track ns occasion requires; lienee a3 a 35 
rod is reciprocated from tho motor through tho gearing described it pushes forward 
during one half revolution tho box or casing which slides upon the rail; upon tho 
commencement of the other half of the revolution by tho action of the eccentrically 
pivoted wheels or rollers tho box or casing is locked to the rail and tho engine is 
pulled up. 40 

Ono only being used tho action would bo a scrieB of pulls and pauses, and if 
desired ono only may be used, taking upon either rail or upon a central rail laid 
especially for this purpose. 

In practice however it is desirable to use at least two, ono for each rail, with 
cranks so arranged relatively to each other tlmt whilo ono is boing slid forward 45 
the other is holding, so that a continuous motion may bo produced. Additional 
grippers or creepers mny also bo placed at tho rear of tho train, so that a continuous 
pulling and pushing action is produced. 

Instead of rollers within the box or casing referred to another form of dcvico 
may bo used, in order to give a larger gripping surfuce. . 5" 

Within tho box or casing are two bars parallel to tho rail, one on each side. 
These bars aro attached to the easing or box by loose toggio joints in such way that 
upon motion forward of the box or casing the bars rccedo from tho rail, but upon 
retrograde movoincnt thoy approach and grip tho rail. ,, 

Another object of this Invention is to produco a sitnplo and effective oloctro* 


_ Jensen's Improvements in Elcctro-m agnelic Railroads, de. 

magnotic broke adapted for use on any stylo of rail road vohicle, but more especially 
intended and adapted for uso in tho system horein described. 

It consists in placing on clectro-mngnet in such relation to some rotatin'* metallic 
portion of tho running gear of the vohiclo to be stopped that tho magnetic cirouit 
5 shall bo through such rotating motallio portion, tho electro-magnet being furnished 
with mobilo heads, which mny movo towards and clasp the rotating portion 
whenever tho circuit of the magnet is dosed. 

Upon tho axle and at or near its centre is rigidly fixed a disc of iron, which 
rotates with tho axle and between tho polar oxtremities of an electro-magnet, 
10 suitably fastened to or supported from the bottom of tho car. 

Tho cores of this electro-magnet aro extended beyond tho coils, forming a spindlo, 
which is reduced in size when necessary, tho ends being screw threaded to receive 

Upon each spindle is placed a block of iron or other magnetic metal, forming a 
15 polar extension secured in placo by a nut. 

The orifices in the blocks into which the spindles pass aro olongated. so that tho 
blocks or polar extensions mny have a movement to or from tho fixed disc upon 
the nxlo rotating between them. 

Tho polar extensions aro normally hold away from the disc by suitablo springs 
°0 of low resistance. 

When is is desired to use the brake a circuit from any suitablo source of 
electricity is closed through the coils of the clectro-mngnots, whereupon the polar 
extensions mutually attract the disc. It however being fixed while thoy aro 
movable the nttrnctivo force causes them to move to the disc and grasp it between 
25 them, enusing n retardation or stoppage of its rotation, and so acting through it ns 
effective brake upon the wheels. Upon breakago of tho circuit tho springs restore 
the polnr extensions to their normal position. 

When desired, for the purpose of throwing the brakes off instantly, a momentary 
reverse current may bo thrown into tho circuit just after breaking, causing a 
30 momentary but instantaneous repulsion from the disc, and assisting tho springs in 
removing tho polar extensions. It is evident that instead or one, several sets ot 
such brakes may be applied to each nxlo when desired. . 

In this system of electro-magnetic railways where the tracks themselves are used 
as the conductors, it is desirable to make some provision guarding against 
35 cessation of effect of the current at crossings, switches, rags, and such^hlce, orother 
places where it mny bo desirable to cut out u portion ot tho track from the 

"tMs may be accomplished by connecting the ends of the tracks in circuit 
adjacentr«.e opposite ends of the cut out section by wire or other conductors, so 
40 that a circuit is formed around such cut out portion 

As the greatest lem'tli of any section necessary to be cut out wilt novel exceta 
thc av 'rag g c length ofa train, or even the length of the shortest trains, it is preferred 

10 AsTforo''described! wheels Imvlng"'STingcs and hubs insulated from each 

“ 5“'b*n»to‘b,i. U g S.1 “■I* 

arranged 1 on* tli'o carsTlmtthcy may ^'electrically bridged over on the 

circuit. 




6 A.D. 1880.— N° 3894. sJSSSSL 

_ Jensen's Improvements in Electro-magn etic Railroads, <tc. 

Upon raids already built and equipped for steam transport, but whero it is 
desirable to use tins systom of locomotion, it may bo profcrnblo to make tbe clian"o 
from one system to tho other gradually. ° 

To admit of gradual cliango, arrangements must bo mado permitting tho use of 
botli systems. j 

To do this, a third or central rail or conductor is used, electrically connected in 
stations of suitable length, and thoroughly insulated from tho bod. To tho caw are 
attached arms carrying rollers or auxiliary wliools, taking upon tho third rail and 
conveying tho current therefrom through tho motor upon tho train, tho ordinary 
rails being used ns tho return circuit. J |q 

In order to most thoroughly insulate tho third or contro rail it may bo placed at 
tho ties in n chair of glass or other insulating mnterial, only morticed into the tic or 
laid on tho tie and spiked thereto, or an iusuluting shield of glass may bo interposed 
between tho rail and n metallic chair. 


A.D. I860.—N° 3894. 

Jensen's Improvements in Electro-mugnctio Railroads, £ 


SPECIFICATION in pursuance of the conditions of tho Letters Patent filed by 
the said Potor Jenson in tho Great Seal Patont Office on tho 25th March 
1881. 

I'eter Jensen, of 33, Chancory Lino, in tho County of Middlesex. “Improvb- 

5 MENTS IN THE CONSTRUCTION OF MACHINERY AND APPLIANCES FOR ELECTRO¬ 
MAGNETIC Rail-roads, and in the Generation, Distribution, and Translation 
of Electricity for Working the same." A communication from abroad by 
Thomas Alva Edison, of Menlo Park, in the Stato of Now Jersey, United States of 
America. 

10 The object of this Invention is to furnish an economical and reliable systom of 
electro-mugnctio railways or tramways, which whilo useful in any locality shall bo 
particularly adapted to regions whero tho trnfiio is too light for ordinary steam 
railways, or whore tho main bulk of the traffic is limited to certain seasons, or 
where tho difficulties or oxpenso of grading remlor ordinary steam roads 
IB impracticable. 

To this ond tho Invention consists in a complete electro magnotie railway system 
embracing tho generation, distribution, and utilization of electric currents ns a 
motive power, and in tho novel devices and combinations of devices therofor, as 
moro particularly hereinafter described and claimed. „ 

20 In carrying tliiB Invention into ofiect tho rails of tho track nro electrically con¬ 
nected, so that each lino of rails forms one half of a circuit. The road is divided 
into sections, whero from its length this is desirablo, each section forming substan¬ 
tially a small independent railroad. For each section a central station is provided, 
at which is located any suitable motor for giving motion to ono or more magneto 
25 or dynamo electric machines connected thereto. At each central s ation, and also 
at other points whero necessary, a portion of a section is electrically cut oS from 
the remainder, which portion boing connected with asiding there laid ena e 
to nass each other. Movable switches or shunts nro formed in the ends of the 
main track adjacent to the sidings. Tho switches are operated by mechamsm set 
30 in motion by olectro magnotie motors having connection electrical’ 

From each end of each rail section connections are mado ™™ 

switches at tho central station, by which means the engneei ov 

enabled to put tho current off or on, or reverse the same on any particular 
switch section, and to opernto any particular switch. mounted 

35 For the travelling motor or locomotive, « S "her 


switch section, and to opernto any particular switch. mounted 

35 For the trailing motor or locomotive, anolcctrom-agnotic engine amounted 
upon a suitable frame, supported upon *[“ • t 0 ther bifnot directly 

whereby the body of tho car and the “ '^bly against hubs scoured 

< Contact springs bear against the flanges, or p.oi n Ui() (lang0Si 
*5 thereto by cross bars or *' spiders whoso ° ute (tor spv i nf r S of tho motor, ono 
Tlieao contact springs are connected to the-cornucontacts l.eroin- 
to each, respectively through tho reveraer and govoinoi contronc 


8 A.D. 1880.—N° 3894,. 

Jensen’s Improvements in EIcctro-magnctio Railroads, <kc. 

force to lio gradually applied to or withdrawn therefrom. Therefore a friction 
wheel is^ mounted upon the shaft of the motor, and ono upon tho main driving nxlo, 
tlio two being disconnected, so that motion is not communicated from ono to the 
other. In a swinging frame pivoted at ono end and provided at tho other end with 
a handle, is mounted another or connecting friction wheel, which on depression 5 
shall take upon botli tho friction wheels before named, and transfer tho forco from 
one to tho other. Of course tho amount of this transferring is dependent upon tho 
perfection of tho frictional bearing of tho intermediate upon tiio other two friction 
wheels, and may bo varied between tho limits of tho minimum and maximum 
frictional contact. Iq 

To accomplish tho samo result a motor pulley and n driving pulley may bo 
connected by a loose belt to bo tightened by n swinging pulley belt tightener, or 
tho snme result may bo accomplished in several other ways. 

As the motive power suflicicnt to move a load upon a level with great speed 
is totally inadequate to move it with tho samo speed upon incline, nnd often fails 15 
to movo the load nt all, means (extra ninount of steam generative enpneity, etc.) 
nre generally used for furnishing a large excess of power over the amount usunlly 
required, adding largely to the dead wuiglit to bo carried. In this system however 
it is proposed to use nt all times for a load or train only the amount of power 
normally requirod under favorable conditions, providing incnns by which speed 20 
is automatically exchanged for power when necessary ; this is to be accomplished 
by a, governor, which, upon speed falling upon reaching an incline, shall auto¬ 
matically operate to alter the leverage either of belts, friction gear, or clutches, 
through which the motor acts upon the driving wheel. As the doviccs for this 
purpose nre applicable to other than electro motor systems they nro not further 25 
herein described or illustrated, but will form the subject matter of a separate 
application for a Patent. 

Upon encli engine is located a reversing key through which tho circuit passes to 
tho motor, which may bo used as a brake in case of emergency, tho reversing 
ol tho current acting to reverse the direction of tho motor, and therefore more 50 
rapidly stop it. 

The operative lever of this reverser is so combined with a Bpring that it may 
bo held in a central position without any of its contacts impinging on other 
contacts, and so act also ns a mere circuit closer or breaker. A centrifugal governor 
driven from the driving axle is used, connected to a series of contncts, ns fully 35 
explained in a prior application, so as to break the circuit nt n number of points 
simultaneously upon a certain pro-determined speed being rcnchcd. 

Provision is made to dispense with tho necessity of much grading, enabling the 
engine to ascend ordinarily impracticable grades as follows:—Upon one or both 
sides of tho engine car a wheel having a grooved fnco adapted to clasp tho bend of 40 
tho rail is mounted in a bearing so combined with a screw or other lifting devico 
that it may bo depressed into or elevated from contact with the rail. Upon its axlo 
is fixed a rag or sprocket wheel. Upon the main driving axle is loosely mounted a 
friction wheel having attached to it a rng or sprocket pinion. To this looso wheel, 
when necessary, motion is communicated from a friction wheoljon tho motor shaft 45 
through an intermediate friction wheel mooted in a swinging frame, ns before 
described j a sprocket chain connects tho sprocket wheel in tho axlo of tho grooved 
wheel and the sprocket pinion. Under ordinary circumstances this friction wheel 
m tho main axlo has no motion communicated to it, and tho grooved wheel is not 
m contact with tho track. 50 

When necessary tho groovod wheel is depressed and tho intermediate friction 
wheel so applied ns to cause tho looso wheel on tho main driving nxlo with its rag or 
sprocket pinion to bo rotated, tho motion being communicated to tho grooved wheel, 
wich grasping and biting upon tho rail head pulls tho load up without danger of ^ 

In figures 1 to 15 of the accompanying Drawings is shown moro in dotnil how 
this portion of tho Invention may bo carried into effect; it is to bo remoinbored 


Jensen’s Improvements in Electro-magnetic Railroads, Ac. 

however, that tlicso details may bo varied or equivalents used, nnd that therefore tho 
Invention is not limited generally in such cases to tho precise details therein illustrated. 

In tlicso Drawings:—Fig. 1 is a view showing tho general arrangement of a 
central station and tho track connections. 

5 Fig. 2, a portion of tho I'ramo of a car. 

Fig. 3, a perspective of an ongino car. 

Fig. 4, a perspective view of the rail gripping doviccs for ascending grades, with 
a section of the grooved wheel nnd rail. 

Fig. 6, a perspective of tho reverser, governor, and tnultiplo circuit breaker. 

10 Fig. C, a bottom view of tho reverser. 

Figs. 7 & 8 arc views of different mechanical means for operating the track 
switches. ..... 

Fig. 9 is a perspective view of tho electrical switches at central stations. 

Fig. 10 is a perspective view showing means of electrically connecting tho rails. 
16 Figs. 11 & 12 are sectional viows showing diflorents ways of electrically 
dividing tho car, so as to insulnto ono flange from the other. 

Fig. 13 is a diagram showing several sections and a side road or feeder. 

Fi“ 14 is a diagram showing connections when desired at a bridge or other short 


dividing tho car, so 
Fig. 13 is a dingi 
Fig. 14 is a diagi 
section. 

20 Fig. 15 is a dingi 
multiple arc. 


n showing the method of connecting the electrical devices ii 


A is a central station, at which are located a steam boiler and engine as shown, 
although tho motor may be a water or any other suitable form of motor; B is any 
suitable magneto or dynamo electric machine, connected with and operated by 
25 tl,e motor engine. From the generator connections 1 and 2 nre made to tho 
switches 3 and 4, ono series being connected to ono commutator, the other senes to 

lh MT“M'Ttnre the main line of track. The rails of each line of rails 
arc electrically connected by means of copper wires or slijs E (lug 10) under tho 
30 fish plate 15, V , and held t^nled 

MT, of suflicicnt engtl. Ml" a".d JIT" At the side thereof and of 

STi SSM 5 V 8W. rie ^rs^S^^i^ 

the ends of MT, arc made movable so as to constitute switches bj u Huh a 
35 may bo switched or-shuntedl&ow , o. U U T, ^ 

For each track switch is arranged an ntwu . * tn Hio other series of 

SJ”"ft-T 1.», -«• «• 

« “X "2 r t. InFig.7 

closed through a switch motor, its motion • which S L is tho 

is shown ono means o so “mnmn.can? motion tott* fol , somo . 

switch lover connected to a double rack it , omn k rod 0, R, either 

what less than half its periphery, the” vitch moto.: 

50 directly or through intermediate gearing, itoll i evol . s L is connected to a 

Fig. 8 shows another way ... wl " "XVcam d whoso shaft carries a 

framo D, sliding in suitablo ways. In ° f ^ gwHflh raolur . The gear and 
gear, into which takes a pinion on tho . needed these switches may bo 

55 located tf? SIXTSi 





30 A.D. 1880.—N° 3894 


Jensen's Improvements in Eleclro-mar/netie Railroads, do. 


switch motor, moving tho switcli in one direction ; the rovorso movemont being by 
a spring. At a little distance on each side of the switch engine are located circuit 
closers, arranged to be hit by an arm projecting from tho train. If a train be 
started, which it is intended shall go oil" upon a switch or branch, the arm on tho 
train is set. On coming to the first circuit closer, tho arm strikes it, closing circuit, 5 
moving and holding tho switch. Tho train passes on to the switch, strikes the 
second circuit closer, opening it; the circuit being now broken, tho spring restores 
the switch. Whoro there aro several switches a permutation arrangement driven 
from tiie running gear of tho train will be upon tho train, capnblo of being sot so 
that it shall project or lower tho nrm for operating tho circuit closers only as it 10 
approaches the proper switch. 

In Fig. 0 is shown in dotail the switches used in tho series 3, 4. Levers a, a, a, 
arc pivoted in suitahlo supports upon tho base 0 ; springs o', a 11 , pulling tho lever 
to tho rear. Upon the bnso are located springs b, b, with their inner onds turned 
up so as to form a catch ’for tho lower ends of tho levers, as shown. From the 15 
springs b, b, of the electricul switch, scries 3, 4, are mndo to each line of rails of 
each track section and track switch, and also to tho switch motors, for instance, 
from M T 1 , wires 7, 7, lead one to 3 and ono to 4. 8, 8, lead in samo way from 
one end of MT, while 11, 11, lead from the other end. In samo way 9, 9, and 
10,10, connect 3 and 4 and S W. By simply throwing tho proper switches so that 20 
they catoli on their respective springs tho circuit is closed to any desired section, 
and tho current thrown therethrough. 

Tho circuit through any particular section being closed, and it forming tho 
conductors for tho current, a circuit is formed from one lino of rails to the other, 
and the current utilized as a motive agent by an engine constructed as shown in 25 
Fig. 3, in which F is any suitahlo frame work suspended from tho main driving 
axle and placed upon the other axle. 

The wheels used under the engine car and all other cars aro constructed ns shown 
in Fig. 11, in which tho flanges FI, are made separately, and connected by a 
wooden web o, to which they are bolted, the wheel then consisting of a metallic 30 
hub, a metallic flange, and an intervening wooden or insulating web. By this 
means the axles and body of the car aro insulatod from tho flanges and track, and 
the current cannot pass therethrough from ono rail to the other. Although both 
wheels in Fig. 11 aro shown ns of this construction, it is evident that those on ono 
side of a car only need be so constructed ns thereby the formation of a circuit direct 35 
from one lino of rails to the other, would bo prevented. Tho samo purpose may bo 
subserved by the construction shown in Fig. 12, in which ordinary wheels aro used, 
tho axle being cut in two and united by a sleeve Q, insulated therefrom by P, and 
bolts insulated from, but passing through the halves of the axles. 

On the ongino car n spider or framo N, (Figures 3 and 11) is secured to the 40 
flange F l, so as to bo in electrical contact therewith, but not touching or forming 
contact with tho hub M. Upon the center of N is a boss or Bpindlo n on which 
bears a commutator brush hold by arm p. The current then passes from ono lino of 
rails through ono flange F l, framo N, boss or spindlo «, commutator p to the 
roversing koy (Fig. 6) tho contact points 13, 14, 15, 10, to tho electric pngino, *> 
thence by tho other nrm p, spindle, framo, and flange to tho other line of rails. 

The reversing key is shown in Figs. 5 and 0, in which U and V are elbow lovors, 
pivoted at Q and Q 1 respectively, the springs s and s l tending to causo them to 
close circuit normally in r and r 1 j V is connected to P 1 , and U to P"; r and r are 
connected to tho series of spring contacts, and then to ono polo of the motor “ 
engine. Between, tho levers U and V is placed tho operating lovor T, pivoted at 
o, and connected to tho other polo of tho motor engine. Upon tho under side of 1 
is a pin s taking into a slot y in a cam pinto w pivoted at x. Tho cam plate w is 
moved ns tho lover T is moved by tho action of tho pin z in the slot y. It is.® 1 
such n breadth, that when standing in a neutral or untilted position, its opposite 
sides shall tako against pins it, v, on lovers U, V, and forco them from their 
contacts, leaving the circuit open. A movement to cither sido however allows ono 


Jensen’s Improvements in Eleclro-murjnctie Railroads, do. 

of the lovers U V, to mako contact with r or r\ the other being kept from contact 
therewith by its contact with levor T. _ Upon tho ongino is mounted a centrifugal 
governor O r,' driven from tho main driving axlo nf tho car. The lower end of tho 
rod, which is reciprocated by tho governor balls, takes upon a lover 17, pivoted 
6 at 18, whose outer end takes under a series of contact springs 13, 14,15, 10, placed 
in the circuit. Tho governor is adjusted to break the circuit whonavor a prodetor- 
• mined rato of speed is reached, breaking it in a number of places simultaneously so 
ns to greatly reduce, if not practically eliminate, the spark due to the breaking of 
the circuit of a large current. 

10 Tho circuit being now completed through tho motor and it being in operation 
motion is communicated to the main driving axle ns follows, reforonco being had to 
Fig 3, in which <J is tho main driving axlo upon which is mounted a friction wheel G. 
Upon tho shaft c of the magnetic engine is a friction pulley e, tho pulloys e and G 
not being in contact. In a swinging frame / pivoted at h is mounted a friction 
15 pulley i. The frame/ being depressed bears upon o and G, and communicates 
motion from e to G, tho percentage transferred being proportional to the frictional 
contact of i upon e nnd G. As giving a better traction to avoid slipping on 
grades a devico shown in Fig. 3 or tho device shown in Fig. 4 may bo used singly 
or together. In Fig. 3, E M is a pair of ordinary electro magnets, there being 
20 one or more pairs on each side. These magnets are suspended from the frame so 
that their poles are over, nnd in immediate contiguity to the rails. From them a 
circuit extends to tho arm p so tlmt they are in a multiple circuit to the track. 
In their circuit is placed a key which may bo operated by hand or which may 
be operated by the govornor automatically under the arrangement heroinbofore 
25 mentioned. Upon coming to a grate tho circuit is closed and tho magnets 
immediately exert their attractive influence upon the track, tending to hold tho 
car firmly nnd to provent its slipping. , ., , , , . „ 

In Fig 4 in addition to to the devices already described as mounted upon shaft c 
nnd axle 3,’ll is a friction pulley loosely mounted upon the main driving axle 3 j 
30 to H is secured a rag or sprocket wheel I. Upon tho shaft 0 is placed a friction 
wheels, nnd in a frame similar to frame/is mounted the friction wheel!; upon 
depressing tho frame motion is communicated from 3 to H and I, winch rotate upon 
the shaft l A wheel L having a grooved face is secured to an axle which is mounted 
in a box adjustably secured to the framo by a sciow S. A s^rockct chain m 
36 connects I and K. Upon reaching a grade by turning Wt 
depressed nnd grips the rail, ns shown, motion bom" 
described, by which arrangement tho engine ca 
common steam rail rode. . 

It should bo stated thall all tho devices usi 
40 mutiplo arc system, the rails forming the d*-" 


. o ...._v S tho wheel L is 

,.ig communicated thereto, os before 
a climb a grade impracticable in 


amp for lighting i:,, 00 fVails of tho track If T. In practice however 

Si'“theTori"^ «■»•* 10 th0 tlnCk - “ nd t0 th0 ar,n9 

and flanges of tho wheels. nnd j[ T 2, onch with a central 

In Fig. 13 are shown two sc • divided at tho station, electrical connection 

- watfsa: 

generator nt tho central station on tho m I ,. , , n bridge, or in any otlior 

In Fig. 14, B 3 represents a.short is insulated iVoni its neighbors, 

locality where it is desired to slow “P- shown at b\ 6", so that upon such 

but connected thereto by wire conductors as shown at , . 1 




12 




13 


Jensen's Improvements in Eleelro-magnetio Railroads, <tc. 


section the current is rcvorsotl slowing the motor, the current being ngnin reversed 
at tiro other end of the bridge soolion restoring tire speed. 

In lieu of this arrangement very short soctions may be disconnected entirely 
electrically, connection being made between the sections adjacent to the cut out 
section by wires passing around such suction, so that tbo motive power is withdrawn 5 
entirely on such sections. 

At the central station it is advisable to place an electrometer in circuit, ns the 
deflection of its needle gives n good indication of the relative position of a train 
upon n section. As at times it may bo necessary to keep tho track clean, frre 
from snow, or other impediments to a good contact between the flange and track, 10 
it is preferable to mount in front of the engines brushes rotating at right angles to 
the rails, and driven by a small motor on the engine car specially set asido for the 

In using electro motors, tho best results are attained when the speed of tho 
rotating armature is maintained uniform and at a very high rate. 15 

In railway motors a largo excess of power over that required for a given speed 
upon a level is provided in order that even a very much diminished speed may 
be maintained upon an up grade, the speed of the motor being diminished pro¬ 
portionately. 

One object of this Invention is to so arrange a motor in relation to the driven 20 
mechanism, that the speed of the motor shall always remnin unchanged, not being 
affected by changes in the speed of the driven mechanism, and that power may be 
exchanged for speed, or vice versa, as circumstances may demand, without the speed 
of the motor being nflccted. Another object is to furnish a method of propulsion 
of trains analogous to the action of a qundruped in drawing a lond, especially 25 
applicable ns means for climbing a grade, or assisting therein. 

To accomplish these objects a thread is mounted upon the shaft of tho rotating 
armature meshing into a worm upon a shaft, at whose opposite end is ft hovel gear 
taking into a bevel gear upon a shaft, parallel to the shaft of the engine. 

Upon this lntter shaft are two gear wheels, one having several times ns many 30 
teeth ns the other, both being loosely mounted upon the shaft, on which and 
between the two gears is fixed a suitable clutch, in order that one or the other 
may be caused to rotate with the axle upon the clutch, being thrown to or near to 
the extreme limit of its motion, but that when the clutch is in nn intermediate 
position, neither shall be locked into tho shaft. In order to prevent the clutch 35 
being moved too rapidly, it may be operated by n screw threaded lever passing 
through the free end of the lover. 

Upon the main driven axle two gear wheels nro rigidly fixed, one large and ono 
small, tho larger ono gearing with the smaller one loose upon the shaft last noted, 
while the smaller one genre with the larger one loose upon such nlinft. 

It is evident then that whether speed bo converted into power, or power into 
speed, will depend on whether motion bo communicated from the shaft driven from 
the armature shaft to tho main driven nxlo, through the smaller or through tho 
larger gear thereon. 

For uso upon grades a device, which may be called a creeper, is used somowliat 45 
ns follows:— 

Upon the front of the engine is mounted a vertical shaft carrying a worm, gearing 
into tho tlirend, upon the urmnture shaft. This vertical shaft is mounted in 
adjustable bearings, so that tho worm may be thrown into or out of gear with tho 
thread, ns desired. Upon tho lower end of tho vertical shaft is a bevel gear meshing 50 
into a bevel genr upon a horizontal shaft, to whose ends by crank nrms or pins nro 
attached rods, each enrrying at its opposito end a box or casing provided with a 
central wheel which rides upon the rail. In tho box or ensing, so as to tnko.upo# 
tho sides of the rail, are ecentriccally pivoted two wheels, one on each side. These 
side wheels being exceniricnlly pivoted, allow the box to be pushed forward along 5i> 
tho side of the rail, but prevent retrograde motion by closing together and grasping 


Jensen's Improvements in Electro-magnetic Railroads, tio. 

tho rail. Tho urms carrying tho grippers or crcopers are mounted so that they 
may bo lot down upon or removed from tho track, as occasion requires. Henco as 
a rod is reciprocated from the motor through tbo gearing described, .it pushes 
forward through one half revolution the box or casing which slides upon the rail. 
3 Upon tho commencement of tho other half of tho revolution, by the action ot the 
eccentrically pivoted wheels or rollers, tho box or casing is locked to the rail, and 
tho engino is pulled up. „ ... 

Ono only being used, the action would bo a series of pulls and pauses, and it 
desired, ono only uiny lie used, taking upon either rail, or upon a central rail laid 
10 especially for this purposo. .... 

In prnctico howevor it is desirable to uso at least two, ono for each rail, with 
cranks so arranged relatively to each other, that while ono is being slid forward, 
the other is holding, so that a continuous motion may bo produced. Additional 
grippers or creepers may also bo placed at the rear of tho train, so that a continuous 
15 nullimr and pushing action is produced. . ... 

Instead of rollcra within the box or casing referred to, another form of device 

iniiv bo used ill order to give a larger gripping surface. 

Within the box or casing are two bars parallel to the rail, one on each side; 
these bare arc attached to tho casing or box by loose toggle joints in such way that 
20 upon motion forward of the box or easing the bars recede from the rail; but upon 
retrograde movement they approach and grip the rail. . , 

Tile operation of tho4 devices will be better understood by reference to 
Figs. 15“ 1C, 17. and 18 of the Drawings, in winch 

PV. 15“ is a perspective view of an engine, embodying both tho motoi and the 


otor, mounted on shaft a, secured in 
ivorm or screw 15, gearing into tho 
id is the bevel gear D meshing with 
ted loosely tho gears F, H ; H having 


a Mason’s clutch. As such clutch i 

encumber the Drawings with a detailed 


Fig. 15 a is a perspective 
25 creeper. 

Fig. 1C and 17 are details of tho creeper. 

Fig. 18 is a perspective view of the motor 
A Ts tho rotating armature of the electric i 
suitable bearings. Upon the shaft a is the 
30 worm gear C on abaft c, upon whose lower 
bevel gear F on shaft c, upon which arc mou 

a much larger number of teetb than F. leev0 c 1 , upon 

Between F and U is mounted so as to rota to w> ■ « the clultc.. Mee , } 
which is mounted a suitable clutch, controlled by bitch:or.Dpjvote 
35 piefcrablo clutch is the 

known it has not been thought necessary to 
view of it. . . ... n ffil . cons t{int rotation of A without 

As hereinafter stated, provision is made either into operation 

imparting motion to F or H. I« ortlc . 1 n . lSsafcCVO w threaded rod through 

40 gradually, avoiding jar or shock, 1 *»"«“ J, und of tho ro d ending in a crank 

tho freo end ol L and at right angles tlieret » , mov i n g the clutch only 

or wheel by which the rod may be turned, each iciolutiou mov.n 0 
the width of ono screw thread. , , a , ■ tll0 nm ;„ driven 

The gears F and H mesh into gears O and I o sliatt g, 

45 axle, carrying wheels, not shown, at its of teoth ns H bears to I. 

Tho gear G bears tho same relation to 1 n „ always bo much less than 

It is desirablo that the «* of . “'ndC'a..d U ami I insures this, tho 

that of A. The relation existing bet" win B* , 01 . lls high as desirable, 

speed of <j liowovor remaining au“>‘ « s . t0 S '.'; " / tll “ t 01l l y the power required 

60 rate of progress to the car, the 1”°“ is furnished, the clutch being 

for the maximum rate of speed and lo " d .T' a f , throu..U II and I. 
thrown so that the motion is commumcaUdtoff « » Umt ia coin- 

Upon reaching diminished by Urn ratio existing 

municatcd through F, G, the speed cause M f 
55 botween tbo two with a corresponding mcreascol ^ ,,„ u . s F, H, is 

ft should bo noted that the relation btt'vro « 0 . .mcatod to 

such that when tho dutch is in a central position no mo 




14 A.D. 1880.—N° 3894. ***** 

_ Jensen's Improvements in Eic ctro-magnitic Railroads, etc. 

either genr, so tlmt when tlio tmin mny bo stopped the motor still rotating at its 
best dleclivo rate ready for instantaneous work with tho delay incident to 
bringing its speed up from zoro to an effective rate. 

From this it can readily bo seen that tho rato of rotation of arniaturo may bo 
kept constant, while tho rate of speed of tho train may bo varied to suit tho various 5 
requirements of change of grade or load, ensuring full utilization under all conditions 
of the prime motor force applied. 

Upon tho front end of the engine car is a shaft h, on which is a sleeve supporting 
tho lower end of a shaft n, whose tipper end is secured in a bearing J which 
permits of n slight movement of tho shaft n. U 

Upon n is mounted a worm gear N, which may bo mado to mesh with the worm 
or screw 15 on tho arniaturo shaft ti. 

Upon and near tho lower end of n is tho hovel gear O, meshing into a bevel 
gear P upon shaft h, to whoso outer ends aro attached tho arms R by means of 
cranks Q. Thc-c arms It are arranged with any simple lifting device, so that they 15 
can be Jot down upon or removed up from the rails. 

Pivoted to It is a box or casing S, in whose upper portion is a wheel u riding 
upon the top of the mil. b 

• nn ^ l, P on wicli side of the mil, wheels 8 aro mounted, eccentrically 

pivoted aa shown, the opening butween them at the widest point being just onough 20 
more than the width of the mil to permit its passugo therethrough. From this it 
is evident that if a body the width of a rail be slid bctwcon then in tho direction 
of thei arrow, Fig. 2, it will push them apart, but that if tho motion bo in the 
body 3 be t wo en* th" ^ CRUHQ tllc roJJcra 8 > 8 > to approach each other, gripping tho 

When necessary the worm N is thrown into gear with B, motion being coin- 
mumcated thereby to the arms R. Upon the forward half of tho movement tho 
arm it pushes the box S along the rail. Upon the commencement of the latter 
hair of the movement the rollers n, approach each other, gripping the track ami 
locking the box^or casing to it, whereupon the car is pulled up toward S. 30 

Where tho rails are light and might possibly be injured or indented au alternative 
th^rail head 11 nm ^ ' v *>ich gives a long grip upon each side of 

In this Figure 4 is a box or frame, connected pivotally to R, and having tho 
wheel u, as in the other form. 35 

Connected to 4 by toggle joints 3, 3, are the gripping bars 1, 2, one on each side. 

As seen, upon motion of the box or framo in one direction, on account of the 
toggle used, the bnrs 1, 2, recede from the rail, but upon motion in the opposite 
direction nppronch the rail, gripping it and locking the box or frame thereto. 

springs may bo applied to the rollers «, s, or bars 1, 2, so ns to normally hold 40 
them to tho rail with a light pressure, not sufficient to interfere with tlioir sliding 
m ono direction, but causing them to act instantly upon attempted motion in the 
opposite direction. 

By the use of the creepers described, the effect of groat traction may bo 
obtained with little weight, bo that tho dead weight of engines and cars may 45 
bo reduced to a minimum. 

Another object of this Invention is to produce n simple nnd effective electro¬ 
magnetic brake adopted for use on any stylo of railroad vehicle, but nioro especially 
intended and adapted for uso in tho system heroin described. 

It consists in placing an electro magnet in such relation to some rotating metallic 50 
I’ 0 '™ °f the running gear of tho voliiclo to bo stopped, that tho magnotic circuit 
shall bo through such rotating metallio portion, the oloetro magnet being furnished 
with mobile bends, which may move toward and clasp the rotating portion whenever 
the circuit of the magnet is closed. 

Upon the nxlo and at or near its centre is rigidly fixed a disc of iron which 55 
rotates with tho axle nnd between tho polar extremities of an electro magnet 
suitably fastened to or supported from tlio bottom of the car. 


Jensen's Improvements in Electro-magnetic Railroads, tie. 

Tho cores of tho oleetro magnet aro extended beyond the coils, forming a spindlo, 
which is reduced in size when necessary, tho ends being screw threaded to receive 
nuts. Upon each spindle is placed u block of iron or other magnetic metal forming 
a polnr extension secured in placo by n nut, 

6 The orifices in tlio blocks into which tlio spindles pass nro elongated so that tlio 
blocks or polar extensions may have a movement to or from tlio fixed disc upon 
tho uxlo rotating between them. Tlio polar extensions nro normally held away 
from the disc by suitable springs of low resilience. ■ 

Whon it is desired to uso the brnko, a circuit from any suitable sourco of 
10 electricity is closed through tho coils of tho oleetro magnets, whereupon tho polar 
extensions mutually attract tho disc.. It however being fixed, while they are 
movablo, tho attractive force causes them to move to the disc and grasp it between 
thorn, causing a retardation or stoppage of its rotation, and so acting through it as 

an effective brake upon the wheels. . ,. . 

15 Upon breakage of tlio circuit the springs restore the polar extensions to their 

""when*desired, for the purpose of throwing the brakes off instantly, a momentary 
reverse current may be thrown into the circuit just aftci breaking, causing a 
momentary but instantaneous repulsion from the disc, and assisting the springs 
20 in removing tho polar extensions. It is evident tlmt, instead of one, several sots ot 
such brakes may he applied to eacli axle when desired. , . . 

This brake is illustrated in Figures 1!) and 20 of the Drawings, m which F g. 10 
is a perepcctivo view of a portion of the bottom of a car, showing a brake , Fig. 20 
shows the polnr extension and spindle of tlio core in detail. nxtendimr 

25 A is the bottom of a car resting upon tlio framing E, E; B is an axle extending 
from whppl CJ to wheel on other side not shown. , , 

fr UpI„ this axle is rigidly secured the iron 

extensions d, d, of electro magnet D suitably secured to t le o J, . ,j 

Each of the cores of tlio magnet extends beyond tlio coils, forming a spindle g on 
30 each core, whose end is screw threaded to receive a nut It. befitted 

Each polar extension d is formed with a elongated slot e so that it n ay be Uttacl 
upon tho P spindlo and be free to move thereon in one direction, vie., to and from the 

Spring k, which may be any of tho arel! known ^ms, is combined with each 
35 polnr extension, and serves normally to hold it ai ) t j s0 t ] m £ the flange, or 
It is evident that the electro magno D ^\Xveef A and they aerate 
a portion of tlio web of the wheel C, si ll [ . tL m “ X o t e I nV ention being 

40 portion. .i-is where the tracks them- 

as as?! S£bfr«» «*. £«- «»»<»* r “ 

“ “sa «,i. fr.—syirs as as ASS 

adjacent to tlio opposite ends of the cut out section oy 

so that a circuit is formed nrond such out J- °"' bo cut ou t will never exceed 

i. ttaSysswt&y *** ** . . . “ p 

■ 

tsszissts. w " s “ J ~ 

a train, one of which ears should always o the last ono 



16 


SpccUtndoil* 


A.D. 1880.—N° 3891. 

Jensen’s Improvements in Electro-magnetic Railroads, <tu 

All tlio commutator brushes used on either side of tho train being connected by 
a conductor tu tho appropriate commutator on tho engino, tiio conductors being so 
arranged on tho cars that they may bo readily connected. 

By this arrangement tho cut out section is electrically bridged over on tho train 
itself, instond of by wires attached directly to tho portions of tho track in circuit. 5 

Upon roads already built and equipped for steam transportation; but whoro it is 
desirable to use this system of locomotion, it may be prcforablo to make the change 
from one system to tho other gradually. 

To admit of gradual change, arrangements must be made permitting of the uso of 
both systems., To do this a third or central mil or conductor is required, electrically 10 
connected in sections of suitable length, and thoroughly insulated from the bed. 

To tho cars aro attached arms carrying rollers or auxiliary wheels taking upon the 
third rail and carrying the current therefrom through tho motor upon the train, 
the ordinary rails being used as tho return circuit. 

This is illustrated in Figs. 21, 22, and 23, in which 15 

Fig. 21 is a perspective of tho running genr of two cars, each provided with 
means for taking the current from tho track, the cars boing connected together. 

Fig. 22, a perspective showing tho third or central rail, and arrangements of 
circuits on the cars. 

Fig. 23, a side view of an engino and car properly arranged, and a cross section 20 
of threo rails with circuit connections. 

In Fig. 21, A and B are two rail sections, B being an electrically connected 
section, while A is cut out from tho circuit at a, the section A representing a frog, 
a switch, or other place where it is necessary or desirable to cut out electrically a 
part of tho track ; C, D, is the frame of two cars, C being tho engino or motor car, 25 
the wheels of which are constructed as beforo described, that is. with tho hub nnd 
ilange insulated from each other, a frame and hub b insulated from the hub of tho 
wheels being connected to tho flange or commutator brush c, taking upon b, and 
completing circuit to the engine. 

Wheels of the same construction aro used with tho car D, which is the lost of 30 
tho train, any number of cars, all or some of which are similarly constructed, being 
supposed to intervene between C and D. 

Preferably the framo and hub upon ordinary cars is upon tho inside of the 
wheels, ns shown at c and /. 

Conductors 1 and 2 run tho length of the train, connecting all tlio commutators, 35 
1 upon one side, nnd 2 upon tho other. 

It is apparent, then, that when tho engine car has passed upon tho cut out 
section tliore will be no cessation of action thereon, ns the current will pass from tlio 
conducting section B, through tho wheels and commutators of car D, by conductors 
1, 2, to the engine. 40 

In the ordinnry electrically connected sections this arrangement has tho advantage 
of making contact with the rails in many places, insuring perfect continuity of 
circuit, and lessening the spark duo to nny imperfect contacts consequent upon 
oxidized spots on the rail. ' 

In Fig. 22,15, E 1 , aro tho rails of an ordinnry rnilroad which it is desired to « 
gradually change to nn electro magnetic systom. F is a third rail, jaid preferably 
between tho ordinnry rails, aud laid in chairs which thoroughly insulnto it from 
the ties. 

From tho one polo of the generator at tho station or source of electricity a 
conductor 5 leads to tho central rail F, wliilo a conductor C from tho other pole # 
leads to both tho ruils E, U 1 ns shown in Fig. 23. 

To the frame of the car is attached, but insulated therefrom, a arm 0, carrying 
a roller or wheel g taking upon tlio central rail F. Connected to this nrin and 
wheel is a conductor 4 which leads to tho motor, from which a conductor J, 
completing tho circuit therefrom through the iron or metallic parts of tho car to tlio » 
rails E, E, which form the return circuit. 

In practice g will bo an extra wheel, in ordor to liavo weight sufficient to always 




A.D. 1880.—N° 3894. 

Jensen's Improvements in Electro-magnetic Railroads, &c. 


17 


insure good contact even whoro tho extra rail is oxidized, it by its weight however 
serving to prevent nny oxidization nnd to keep the surface of tho rail bright. In 
tho Figures it is shown as more of n rollor than a wheel, as to have shown it full 
sizo would have obscured other portions. 

5 It is prcfcrablo to use a rail for tho extra conductor, inasmuch as a large mass of 
conductor with littlo resistance is given thereby at loss cost than to use a copper 
conductor or ono specially prepared for tho service, and as they are generally easy 

By using ordinnry rails for F, and ordinary wheels for g, not special appliances 
10 need to be prepared while tlio change is going on, the method shown demanding in 
its carrying out only tho materials usually on hand, or easy of obtaineinent and 
capable of uso for their ordinnry functions, when their use in this connection is no 
longer needed. 

When it is attempted to uso the rails of a railroad track, ns herein sot forth, ns 
15 the conductors for nn electric current, there is nlways more or less surface 
conduction, tho amount depending on the hygroinetric conditions of tho adjacent 
soil, tho tics, etc. 

To largely rcduco or prevent entirely this surface conduction it is preferred to uso 
means substantially ns follows:— ... 

20 Between the rail nnd tie is placed a piece of felt, papier macho, or other flexible 
insulating mntorial, preferably so treated ns tu make it waterproof, which piece 
extends upward on tho web,'on both sides of the rail to the head, forming an 
insulating shoe. , „ , , „ ,. 

Between it and tho spiko is plnced a piece of metal of tho general configuration 
25 of tho foot of the rail, upon which the head of tho spike takes and bears, so that 
the insulating material is protected from abrasion or damage by the spike. 

Instead of this metal piece a much heavier pieco of wood may be used, forming 
a shoo fastened down by tho spike, nnd in turn securing the rail. 

Tho foot niul web of tho rails are covered with some elastic insulating composition, 
30 for example, a rubber paint, or a paint of which tho base is pure linseed oil; tho 
ties for i! space of, say, ono half foot to a foot on each sido of tho rails being 

35 m “idtatt.. tic. or l.td oo tl* tic ..(I ““"H ,l, ‘* ld 

of gloss mavbc interposed botweon tho rad and a niotaUic chmr. 

\Vl,;in this clmir of frlass or other insulating mateual is hero spoken ot in 
connection with tho third or central rail, it may bo used with any rails forming 

4. ““‘3- l»..l.ti." » '« ** **■ » » "• *» 

30, 31, 32, 33, 34, 35, and 36. . , „ P i.* nnnipv mnclid vulcanized 

45 8l ‘C Figures 24. 26, and 27, is a washer piece of metal which is placed between A 
nnd the spikes c, protecting A from injury by. the' spAM- b() ^ 

In place of tho piece C woodon pieces D, 1 8 * > . t ,f soluo clastic insulating 

Tho foot b and web ct of tlio ra ' ls ^ ro 1 t " ( ?‘ )0sedi or in condition to forma 
60 composition, leaving only tlio head of the r . ] 

connection for conduction of current. liaviu" n bnso of pure linseod 

This composition may be a rubber paint, or n paint havm„ l 

oil or any oxidiznblo oil. . f 0 f j,isulalion referred to 

55 

"TfSfi Z 3 u ,w i.»** - - 1 ’™ '"‘f“ ” 







Jenson's Improvements in Electro-magnetic Railroads, Jo. 


wood, tlio base K of tlio clmir being of ono picco, the rail rosting in a recess in 
which it is secured by wedges L of insulating material. 

In Figs. SO & 31 tlio clmir is of nti insulating material, say, glass, mnde in two 
longitudinal halves, each having a recess tlio slmpo of half tlio foot of tho mil, 
encli half being slipt upon tho foot. 5 

In Fig. 30 tlio clmir has outwardly bevolod sides which toko into mortices in 
tho tie, while in Fig. 31 tlio chair rests upon tho tie and is spiked thereto. 

In Figures 32 and 33 tlio foot of tho rail rests upon a piece m of insulnting 
material, while pieces n, n, of tlio samo material aro laid on tho lop of the foot, 
half chairs o being placed to hold tlio whole together and then spiked to the 10 
tio directly in Fig. 32, while a metallic base plato P is placed undorncatli in Fig. 33. 

In Figures 34 and 35 an insulating bed plate r of the width of tho foot of tho 
rail is used, pieces It being used over tho top of tho foot, the whole held together 
in position by metallic half shoes Q spiked to the track. In Figure 31 tho 
bed piece r lays upon tho tic, while iu Figure 35 it tits into a bevelled mortice 15 
therein. 

In Fig. 36 a metallic shoo iu ono piece is used, in which is a large recess with 
bevelled sides, in which the (insulating shoe composed of base V and side piece T 
is placed and secured therein by tho wedge U. 

These plans aro all unitary, in that in all the foot of tho rail is so surrouded 20 
by insulating material ns to completely avoid the surface conduction duo to 
contnct with damp ties, etc., mid differ mainly in tho forms given tho inotallic shoo 
which protects the insulation and serves to fasten tho rail and insulation together, 
and both firmly to the tie. 

While any insulating material may bo used, the best results are attained with 25 
glass toughened by any of tho know processes for toughening it Such glass 
stands any jar or shock well, not breaking or ernking under any ordinary wear 
otid tear. 

Wn.VT IS Cl.AI.MUD IS,— 

1st. A system of electrical rail roading in which a road is divided into electrical 30 
section, the rails forming tho conductors, each section provided with a central 
station at which is located a suitable engino; a generator of electricity and means 
for controlling and completing tho circuits to trains and to switches ; cars which 
are electrically divided so tliut the motors thereon aro insulated from the track; 
and means for completing the circuit from lino of rails through the motor, 35 
substantially ns set forth. 

2nd. Tho combination with a track switch' of an electric motor and circuit for 
operating the switch, substantially as set forth. 

3rd. The combination with a car frame insulated from the track of an electric 
motor, an olectric traction devieo and lamps, or of any two of them when they aro 40 
arranged on multiple arc or derived circuits, substantially as set forth. 

4111. The combination with a car frame of an electric engino for actuating tho 
car, mid having its inducing and field of force magnuts iu separate derived or 
multiplo arc circuits, substantially ns set forth. 

6th. The combination with an olectric engino mountod upon and, actuating a car 45 
of a circuit revorser, and means for operating tho rovorscr from a distant station, 
substantially as set forth. 

Oth. The combination with an electric engine mounted upon and actuating a 
car and the main driving axle of a governor receiving motion from tho latter, and 
operating to break tho circuit of the engine upou tho nttninomont of n pre- 6l> 
determined rate of speed, substantially ns set forth. 

7th. Tho combination with a main electrically connected rail section of a short 
section connected to the main section by conductors, arranged to change tho 
polarity of tho current traversing cacli line of rails, substantially ns set forth. 

8th. A car wheel constructed of n metallic hub and a metallic center unitod by »• 
a wooden or insulating web, substantially us set forth. 


Jensen’s Improvements in Electro-magnetic Railroads, tic. 

9th. A car in which an insulation is so applied that the body is elcotricully 
insulated from tho flanges of tho wheels, substantially as set forth. 

10th. The combination with an electric engino mounted upon and actuating a 
car nnd tho main driving nxlo of a loose or flexible connection for convoying 
6 motion from one to the other, substantially ns set forth. 

lltli. The. combination with a car of a magnet or magnets operating upon 
closiiro of circuit to incrcaso tho traction of the car upon tho track by their 
magnetic influence, substantially as set forth. 

12th. Tha combination with tlio insulated flange and the contact spring for 
10 convoying the current therefrom of several multiple are circuits, each containing a 
device used in running, controlling, or lighting a car, substantially as set forth. 

13th. The combination with a car of an additional grovo faced wheel mounted 
in.an adjustable bearing, means for elevating or depressing tho wheals and its 
, bearing, and a loose or flexible connection therefrom to the main driving axlo, 
15 substantially as set forth. 

14th. Tho combination of a loose friction pulley on the main driving axlo, a 
friction pulley on the motor shaft, anil a swinging or movable pulley for con¬ 
necting the two, a sprocket wheel on tho loose pulley, a sprocked wheel on tho 
shaft of the grooved wheel, and a sprocket chain, substantially ns set forth. 

20 15th. The combination with the operating lever of a circuit reverser, of a cam 

plate normally holding tho swinging levers of the reverser out of contact with 
their anvils and always opening ono circuit beforo closing another, substantially as 
set forth. . . 

lOtli. The combination upon one car of an electric engine for actuating the car, 
25 circuit reverser, a centrifugal governor acting to make or break the circuit, and a 
magnet or magnets operating to increase the traction of the car upon the track, 
substantially as set forth. ... , , „ e 

17tb. The combination with main driving nnd ordinary wheels of a car ot a 
wheel minuted to onisn tho track and to bo brought into operation ns desired, 


magnet or magnets operating to increase the traction of the car upon the track, 
substantially as set forth. ... , , „ e 

17tb. The combination with main driving nnd ordinary wheels of a car ot a 
wheel adapted to grasp tho track and to be brought into operation as desired, 
30 substnntiallv as set forth. . , r n , , a w 

18th. Th'e combination with the main track section of the section J1 1 and 
and circuit connections and switch motors, whereby trains may e posse y e 

° mh 8 tn"a n n "Z“o S muSiic railway engine, the combination with the motor 
35 aud it driven axle , f t s of variable gears a id.a cluteh tor jmying the 

r “ 20th! IdmeolbiltTrwitl, iTeleriro T„X' 

Zi'iSS S **> 

40 described. nnn reciprocated from the prime motor of a 

us shown nnd described. . „„ s i 10 , vn consisting iu first 

45 22nd. The method of propulsion, jubs «nt,« y to°the track, 

sliding forward a mobile port on ot “ 0 Xn’,ute"anti«lly a. set forth. 

and causing tho load to approach sue withoufc j ncl . enso of weight 

23rd. 1’ho method of = t0 t l l0 track, substantially os set forth. 

“ “Srs'sEl**!. b ” i ““ s “‘ 








SpwUrallou. 


20 A.D. 1880.—N“ 8894. 


Jensen’s Improvements in Electromagnetic Railroads, Ac, 


constructed to grasp between its poles a rotating portion of or attached to tho 
running gear, substantially ns sot forth. 

27th. The combination of a series of insulated whcols and commutator brushes 
on different cars of a train, and circuit connections through all upon onch side 
respectively to tho motor, substantially ns sot forth. 5 

28th. The combination of an extra rail connected electrically in sections, nnd nn 
extra wheel or wheels upon the car frnrno or car frames, but insulated therefrom, 
for completing the circuit, substantially as set forth. 

29th. Tho combination of nn extra insulated rail, olectrically connected in 
sections nnd connected to ono polo of tho source of electricity, with the ordinary 10 
or traflic rails, ono or both connected to form the othor terminal of the sourco 
of electricity, or ground, or part of the return circuit therefor, substantially as set 
forth. 

30th. Tho combination with the rail of a glass or insulating shoe, substantially ■ 
ns set forth. 15 

31st. The combination with the rail nnd n metallic shoe of glass insulating 
plates interposed between tho rail and shoo, substantially ns set forth. 

32nd. The combination with tbo rails of a track forming nn electric circuit 
of nn insulating cushion or shoe placed betweon tho rails nnd ties, substantially os 
set forth. 20 

33rd. Tho combination with the insulating cushion or shoe interposed between 
tho rails nnd ties of a solid washer or piece placed between tho spike and cushion 
or shoo for protecting the latter, substantially us Bet forth. 

31th. A lino of rails electrically connected to form a circuit or part of a circuit, 
and having the foot and web of tho rails covcrod witli nn clastic insulating 25 
composition, substantially as set forth. 

In witness whereof, I, the said Peter Jensen, have hereunto set my hnndnnd 
seal, this Twenty second day of March, in tho year of our Lord One thousand 
eight hundred and eighty one. 

PETER JENSEN. (l.s) 30 

































































A.D. 1880, 30 th September. N° 3964. 


Magneto-electric Maohinea, &o. 


LETTERS PATENT to Peter Jensen, of 33, Chancery Lane, in the County of 
Middlesex, for an Invention of " Impbovements in Magneto on Dynamo 
Electbic Machines, Applicable to both Generatoiis and Engines.” 
A communication from abroad by Thomas Alva Edison, of Menlo Park, in 
tho State of New Jersey, United States of America. 


PROVISIONAL SPECIFICATION left by the said Peter Jensen at tho Office of 
the Commissioners of Patents on tho 30th September 1880. 


the Commissioners oi raterne uu wi« ^ 

‘ bL’Z'SXZ. Vailed Stela etlm.iive 


A portion of the Invention relates to Moists of a bundle of 

»-• "l b "” h in ■” h 

10 os to bear upon and make contact with ausually been rigidly attached 

As hitherto constructed the ^to different 

to the frame of the machine, with some,taa for “J ^ ifacom _ 

positions with relation to the commit , and a lacomout| a stoppage of 

mutator brush become so damaged as to neea repair i 

16 the machine was necessitated. ■ b sbea upon the periphery of the 

It is important that the pressure °f, , . Bn + to the desired degreo, as 

commutator should be “^ire toJ rapidly abraded and worn away, 

20 thereof, causing them to be bunt or oxidized. .---’ '» 


thereof, causing them to be burnt or oxidized. permitting the removal for 

rep^f^ 

Jn, nr the current transmitted. _ _ 


repair or replacement ot a Drusn re l 

with its capacity or the ou " ent n ‘[.TS or snring is secured in a holder having an 

26 aiSTSfflr^ *° be “° bliqUely 7 0nth9 : 


[Price 10i.] 





Jensen’s Improvements in Dynamo-electrio Machines, <£u 


commutator, Hint is, at an anglo otlior than a right anglo with the axis of the 
commutator. 

This holdor is pivoted in a U sliapod jaw in tho top of what is afterwards tho 
stain or shank of tho holder. 

At the pivoted point of tho holdor is n chamber in which is a spring, whoso forte 5 
is oxerted to throw the brush upon tho commutator, a ratchet wheel and pawl 
being arranged in connection therewith, so thnt tho force of tho spring may bo 
adjusted. By this means an adjustable spring seated commutator, brush, or spring 
is secured. 

Upon one side and near tho lower ond of tho shank or atom is a recess, into 10 
which from below passes tho ond of a sot screw. In front of tho commutator are 
two metallic conducting bars, each forming ono tormina! of tho exterior circuit. 

These bars are of tho sizo of tho recess in tho stoms or shanks last described, and 
aro provided with a groovo in their under surfneo. 

Upon each of these bam two, throe, or more of tho adjustable spring soated 15 
commutator brushes are placed by slipping tho recessed portion upon tho bar, thoy 
being then secured thereto by turning tho set screw until its ond takes in tbs 
groovo in tho bar. 

This arrangement nffords lnrgo contact surface, whilo at tho samo time any ono 
brush may bo removed for repair or replacement without interference with the 20 
generative capacity of the machine or disturbance of tho current. 

Another portion of tho Invention relates to tho combination of tho primo motor 
with the magneto or dynamo electric machine. 

In using magneto or dynamo electric innchines it is very important thnt tho 
nrmnturo should be rotated at an uniform nnd constant si>eed, ns any variation 25 
therein immediately manifests itself in the current. 

As ordinarily used, such machines are connected to tho primo motor by inter¬ 
mediate gearing, usually belts, which are liable to slip, causing irregularity in tho 
rotation of the nrmnturo or bobbin, every such irregularity affecting the current, 
causing tho irregularity to bo repeated and shown in the operation ofwhntevor30 
translating devices are used in tho circuit. 

To obviate this it is proforablo to connect the primo motor nnd tho generator 
directly, that is, supposing tho prime motor to bo n steam engine, tho pitman rod 
of tho engine is connected directly to tho shaft or nxlo of the revolving bobbin, 
preferably by a crank pin on a disc upon tho end of tho bobbin shaft, which disc 35 
is weighted upon tho side opposito to tho crank pin with a weight which counter¬ 
balances tho weight of tho pin and pitman, so that any jar or irregularity in 
passing dead centres is obviated; this arrangement is specially needed as the 
ongino used should bo one of very rapid stroke, not less than four hundred to five 
bundled por minuto, in ordor thnt tho bobbin may recoivo its needod high rate of W 
rotation. The ongino should also bo what may bo called “a self contained engine, 
that is, provided with a governor and au automatic variablo cut ofr, which may 
bo so adjusted that upon tho speed becoming too great, tho cut off shall bo 
automatically changed to cut off at a less fraction of tho stroke, and vice versa. 

c 9 ursc > as tho speed of tho engino lessens tho rate of tho rotation of the J 
bobbin is lessoned, nnd consequently tho electro motivo force or “ pressure ” of the 
generated current drops. 

If the steam engino nnd generator bo so arranged, there is provided a system o 
generation in which automatically tho pressure or force of the current may be 
mamtainod constant. 5U 

In manufacturing generators of large capacity, very largo cores and very largo 
castings for polar extensions aro required. Theso very largo parts cost more 
proportionately than small ones, nnd are much more difficult to handle, the winding 
of them requiring greator labor and care. . , ,5 

.ho greatest effect upon tho cores is given by tho coils nearest to it, but in 
lmug very large cores somo of tho coils aro nocesBarily somewhat distant fro® 1 


BpwJlIcatlon. A.D. 1880.—N° 3964 3 

_ Jenson's Improvements in Dynamo-electric M achines, <fu “ 

With ssvoral smaller cores whose aggregate of weight is that of one larger core 
a larger surface for tho action of cods may bo obtainod and a larger amount of 
wire used, whoso averago distance from the surface of the cores in either case is 
tho same. 

6 Generators of very great capacity may therefore bo profitably constructed of a 
senes (two or more) of coils and cores or field magnets, each sot having its own 
polar extensions, but ono armature or bobbin common to all being used. 

By such construction, ns boforo explained, ease and economy of construction are 
secured, tho coils ure brought on nn average nearer tho cores, and a gronter amount 
10 of wire inny bo profitably usod; moreover, if at any time it is desired to increase 
tho capacity of tho generator it may bo dono by adding more field magnets to those 
already in tho generator, tho only now part required being a proportionately longer 
bobbin. 

As ensuring compactness and strength it is preferable to mount the engine and 
15 genorator upon ono base, on which is secured upon intermediate supports of a non¬ 
magnetic substance tho genorator, tho non-magnotic supports being necessary to 
avoid the formation of a magnetic outsido of the polar extensions. 

In order to give greator rigidity and needed support to the generator the series 
of polar oxlonsinns are united physically by a brace or union of non-magnetie 
20 material, which in effect makes the opposite poles ono structurally, but preserves 
them separate magnoticnlly. 

Another portion of this Invention relates to tho governing or regulation of theso 
machines when usod as enginos for tho conversion of current into power. 

Governors as usunlly hitherto made for such engines havo been arranged to 
25 break the circuit upon tho occuranco of a too great speed, tho circuit being again 
closed upon the proper lessening of the speed ; but it is evident that tho abnormal 
speed will be continued by tho momentum of tho parts for a greater or lass interval 
after tho breakago of tho circuit. 

This plan gives rise to undesirable variations in the speed of the engine, as the 
30 speed must first rise when tho circuit is broken, tlion fall when it is again com¬ 
pleted, thus alternating in rise and fall of speed, ofton giving a jerky motion to tho 
engino and connected gearing. .... 

Tho bettor plan would seem to bo to so arrango tho governor that ordinnnly tho 
abnormal or greater than desired speed should not bo reached, the speed being 
35 maintained practically uniform. , . ... 

The object of this Invention is to accomplish tins result, and to that end it 
consists in a governorby which tho circuit is broken at regular “ t ? rva “- 
once in every revolution of the governor, and ordinnrily [ at a certain.jammed 
point, tho ongino running by momentum until the circuit bo a S alrl “ P euttinir 

their lino of union being a diagonal, that is, it the s n ^ ^ w tha 

flat it would bo of the shape of an itaht A, th , this spindle and tho 

60 diagonal connecting tho legs of the If. A spring beam upon tins spimu 

circuit to the engino passes through the s P nn 8 p ,,, j proper Bp eod and with 

The governor is so adjusted that ^" l^^irVeTn 'Z rigEt position for 
the circuit tobTcompLto during 1 enough of each rotation of the sleeve to maintain 

“ tit 

tho governor slowing will cause the current to bo on for a greater p ^ 








_ Jensen's Improvements in Dynamo-electric M achines, <tc. 

rotation, or, so to speak, will cut off at a great fraction of the stroke or via 
versa. ’ 

Another portion of the Invention relates to means for communicating motion 
from the rotating nrmnturo of an electric engino to tho driven mechanism without 
tlio use of belts, gem's, or other similar devices used to diminish tho speed. 5 

The best elici ts nro obtained from electric engines when tlio armatures are 
steadily and uniformly revolved at a very high speed. 

1 his rate of »po> d is oftentimes, or rather generally, greator than the rale at 
which it is desired to run the driven machinery ; in order therefore to reduce the 
speed tlio motor and driven machinery nro connected by bolts or gearing, in whose 10 
uso there nro inherent defects, such as tho slip and strotch of belts, tho rattle of 
gear, and so forth. 

Tlio method which I have devised for this purpose may bo stated in coneral 
terms as follows b 
Tlio rotary motion of the armature is first converted into an oscillating motion, 15 
winch is then converted into a continuous rotary motion in tho following 
way:— ° 

Upon the slinft of the armature is a balnnced crank pin to which is attached a 
pitman or driving rod connected to an oscillating frictional pawl mechanism. 

Upon the driving shaft is fixed a wheel having a frictional periphery. Loose 2U 
upon the driving shaft is an nrm extending a distance nbovo the rim of tlio frictional 
wheel, and then bent over nnd fashioned into a frame, in which are pivoted two 
paw s connected together by a frame capablo of being shifted, so that only one 
pawl con tnko at tlio time upon tlio wheel. 

1 lie pawls aro so constructed that they communicato motion in opposite directions, 25 
hence the direction of rotation of tho driving wheels depends upon which one of 
the pawls is used. 1 1 

The arm carrying thepnwls is slotted, and tho pitman or driving rod is connected 
thereto by a pin whoso position is adjustable in tho slot, so that the leverage may 
be adjusted and tlio speed communicated onsily varied. 30 

The arrangement described is used in duplicate; that is, two or moro driving rods 
communicate motion from tho nrmnturo Blmft to os many frictional pawls and 
driving wheels on the driven shaft, tho crank pins being so arranged relatively to 
each other that a continuous motion is imparted to tho drivon shaft, and mechanism 
connected therewith. 35 

Upon tlio driven shaft is loosely mounted the fly wheel nnd main driving pulley, 
n clutch being used to fasten them to tlio shaft when it is desired to communicate 
motion, so that tho machinery may bo slopped without stopping tlio motor itself. 

bomo methods by which power could be readily and economically transferred to 
a aistanco from a prime motor has long been folt to bo desirable, und to tlmt ond •»<> 
many suggestions have been made and plans devised involving its transfer by ropes, 

by compressed air, and by electricity. 

Practically it lina been determined tiiat the power of a primo motor may bo 
converted into electricity, nnd the electricity convoyed to a distanco to bo 
re-translated into power; this, however, only to a limited extent and by the uso of « 
y nigo conductors, for to transmit power to any great distance without the uso 
^ g0 and °°, at| y conductors, requires that the current should Imvo very great 
electro-motive force or “ pressure,” say ns much as two tliousnnd to threo thousand 
Wltl ‘ ““Eneto or dynamo olootrio macliinos ns now built.it is 
impracticable to gonorato currents of such high electro-motive force. 80 

one r?:!?“r in ? s bavo but a 9 ' n 8 l0 bobbin - nnd tho difference of potential between 
section of wiro upon tho bobbin and another would bo very great, 
hv if 1111198 90 8 re ®^ a difference of potential it is extremely difficult to guard even 

by the most careful winding and insulation. • 

4e ™™?V 8p ?° iall J r in dani P woathor or when tlio bobbins bocomo damp, that 55 
eats break a short path from sootion to section, burning tho wires. 


Jensen's Improvements in Dynamo-electric Machines, £c. 


In addition such great electro-motive force causes a large increaso of destructive 
spark nt the commutators. 

If currents of such electro motive-force could be safely nnd economically 
generated nnd translated, exceedingly Btnnll and inexpensive conductors relatively 
5 could bo used to transfer, without material loss, a very largo amount of power, say, 
several hundred horso power. 

Another object of this Invention then is to furnish means and methods by which 
this transmission may bo made. 

In systems of this kind a primo motor is used which may be an air, Bteam, 
10 water, engine, windmill. 

A high speed engino should bo used geared directly to the generator. 

When a wator wheel is used, bucIi as ure now ordinnnly used, oil account of the 
low spcod with ordinary bends of water it would have to be connected to the 
generator by gearing, ordinarily belts, arranged to increase the speed so as to give 
15 tho bobbin a sufficiently rapid rotation. Tlio uso of belt3 or gearing however 
involves k>3s of powor nnd irregularity. _ 

Still nnothor object of this Invention then is to so arrange water wheels in con¬ 
nection with generators that the wheel nnd generator may be connected directly 
and without intermediate gearing, and still the necessary high speed obtained. 

20 To accomplish these last named results n battery of generators is used, each 
separntoand complete in itself, but with all the rotating armatures or bobbins 
(each provided witli its own commutator) mounted upon tho same dr.vmg shaft 
the total electro-motivo force of all tlio bobbins bemg equal to the electro-motive 

25 ^By'thu^d'ividing it between a number of bobbins it is lessoned ini each bobbin 
with a consequent reduction of difference of potential between the layers or sections 

on each bobbin. are divided up in the same way, all tho 

—* -F- 

"’■“Arrrw rr 

speed it should boused to actuate a pumping a PP aratas - 1ra ““f ller wheel geared 
hight whence it may flow under great head or ^ to of tho second 

directly to the generator, tho iiicreased liead o wat ^ becaugn the lo39 

35 wheel resulting in an accelerated velocity, tins | wheel is less than the 

in pumping and using tho pumped water to drive the: sreotid vhe 1 .s 
loss due to gearing by belts and such like « s ow moving 
in such manner os to give tho desired high ve<Ki . an( j commercially prnc- 

By the arrangement thus generally stated it P . pr ime motor into 

10 ticablo to convert even soveral thousand horse p small conductors 

electricity, convey the electricity by moderate sired or even y 
to a distance, there to he reconverted into power. . mua t exist botweon tlio 

In addition, for tho best results, certain relat 
generator and engines. _ ll j-i 1 is suonlied to nn electric engino, 

« In using generators to produce a current, wmeu o ‘ l tran3miu ; ng machine and 
the practice hitherto lias boon to mako tho 8 ^ when each is rotating at 

tlio engine or receiving maehino exactly nh , . y( , r es00 tly equals the electro¬ 

same speed the counter electro-motivo f “ rc0 ° hen n0 work is being done, the 
motivo force of tho generator. In such cos > wte of S p ee j which is necessary 
50 tendency of tlio engine or receiver is toaul * ,: vo f orc o about equal. As w° 
to mako tho countor and tlio primo ?' ectr ’ nt | y its counter olootro-motive > 
given tho engine to do, its when dob« *» ™;jg 


55 point reducing its speod, and consequently 


s countor electro-motive - 

force and tho counter electro-motive 









Speculation. 


A.D. 1880.—N« 3964. 


Jensen's Improvements in Dynamo-electric Machines, <tc. 


force (of course less friction, for oxamplo), represents Urn amount of current Irons- 
forrod into power, winch in most cases is not inoro than fifty per cent. 

Instead of the nrrangoinent dosoribod tho bobbins of tl 10 receiving machines nr 
engines are wound so that when driven at tho same speed as the general 
transmitters their counter olcctro-motivo forco shall be only one half or ev«Th.« a 
that of the transmitters. * Iess * 0 

Unloaded then, ns their tendency is to run at the rnto which shall dcvolono tho 
same eleetro-motivo force, they rotate at twico tho speod of tho generators. P 
Now if they are so loaded with work as to reduce their speed to tho same as 
that of the transniliters they devolope only .half their unloaded counter electro 10 
motivo force, turning fifty per cent, into power at that rato. 

nfa.nn!!,! n?l 0 n ,0B ?u U ! 0 ? n ? ino witb work °'>ly to that point which permits 
of a speed not less than that of the gonerator, and usually somowhnt greator, so that 
t n C n 0 r;,',‘ ter i 0 f tr0 '' I ,'° tlV r f ° rC0 dov8ll T od slm11 b ° "bout soventy five per cent, of 
tlio prime electro motive force, at about which point is the Greatest economical 15 

ry"bTfolIowefift'oth" COnnCCtillg “ P thB 8 enorator8 ««1 engines tho same plan 
, n n^r t0d l Pre r 0USl /,i Uta 8mnI1 currontis squired to knep up to tho point of 

magnotic saturation field magnets onco brought to that point. P 

rnaimot^wi ’f CUrr ° n t generat0d “ tok8 " through tho coils of tho field of force 20 
thc ™‘ a ™';y t-'nen as much current as needed for tho purpose, and the 
ouenl vTlUn 16 / 10 ' ^ 01813 u f less| y add nd to tho circuit of tho current, consc- 
Sm bobbin ^f P ^ !md „ t0 ,. use on y part °f the current, arranging a shunt circuit to 
fields nf b .11 ° r “ tlie rnaclmies, which shunt passes around and energizes tho 
motive^ ' n Ule r i8ta r of tlle fioIdB iB Proportioned to tl,eclectic- 25 

tl °u \° h° b . b ! n ' 80 th,,t on 'y tbo Proper proportion of current will pass 

through the shunt, that is, just enough to keep tho field magnets up to the point 
of economical magnotic saturation. 1 P 

J n,mturo us cd at presont is ono composed of a number of 
r i w 0,, “' lW ?' ,lly ° v r 11 8in 8'° core . the coils crossing each other at the 30 
ends where there is a largo and cumbersomo mass of wire. 

rliffi„,.it C , ltt !'. C ° one or lnore eoils aro injured or destroyed tho repnirmont is a 
which nvprlnn t° U , S i P™ 08 ? 8, 8ucb c0 ‘ ls were among tho first put on those 
removed " P 1 1 Cnds mU8t b ° romoved boforo tbe injured ones cun bo 

8Uch P rovision be rnnde that any coil can be removed or 
repaired without disturbance of tho remainder. 

this object p0rt '° n ol t,ie I uve, ition therefore relntcs to a construction for attaining 

„ ™V?“ BC °";P lial ! ed b y making of wire only that portion of tho coil which is 40 
rnuf««° r fV V0 fa ?°’ 110 wires of a coil being connected at the cuds by metallic 
are m, l 4eDed nn | n8 ulating base and insulated from onch othor. These plates 
at wlnni? b0 - aB . ^Project at the proper poiuts above tho general surfaco of tho core, 
devices tbe T® 8 ? r ° 8ccur ? d tliom by soldering, brazing, or clamping 

block. At 0n ° ° Dd 0801 P * ttto “ suitnbl y connected to the propor commutator 43 

° { e cm ? val of “y ooiIs ifcia unloosed from its plates at cadi 
to remove t rfn .^ rba a C0 of 1 otbor colk In fact, by such construction it is possible 
machine nnH w'm ' a"? ro I )laco an y coil without taking tho armature out of tho 

. bu4 , “ sli 8''t stoppage of tho machine 50 

from each othec^i 4 . 1 ! 0 ond . nre “ ado 118 concontric almost semicircles insulated 
thereto th U * 110 P ro J octlon8 I 01, receiving tho wires nearly at right angles 

r Jstonce^n.o 0 ^'' le f r . esiatanco t,mn ‘ho wire, and consequently tho internal 

resistance of the generator is proportionately reduced. 65 


A.D. 1880.—N° 3964. 


Jensen’s Improvements in Dynamo-elcclnc Machines, <to. 


SPECIFICATION in pursuance of tho conditions of tho Letters Patent filed by 
the said Peter Jenson in the Great Seal Patent Ollico on tho 30th March 
1881. 

Peter Jensen, of 33, Chancery Lane, in the County of Middlesex. " Improve* 

6 ments in Magneto on Dv.vamo Electric Machines, Applicable to both 
Generators and Enoines.” A communication from abroad by Thomas Alva 
Edison, of Menlo Park, in tho State of Now Jersey, United States of America, 

A portion of tho Invention relates to the commutator brushes. 

As iB well known the commutator brush generally used consists of a bundle 
10 of wires or layers of sheet metal fastened in n frame or brush holder in such 
position as to bear upon and muko contact with tho commutator. 

Ab hitherto constructed the brush holders have usually been rigidly attached to 
tho frnmo of tho machine, with somo device for adjusting them to different positions 
with relation to tho commutator, and also so attached that if a commutator brush 
15 become so damaged as to need repairs or replacement a stoppago of tho machine 
was necessitated. 

It is important that the pressure of the brushes upon tho periphery of tho 
commutator should bo constant and capable of adjustment to the desired degree, as 
when tho pressure is too greut the parts are too rapidly abraded and worn away, -g 

20 and when too slight an are nmy form between the opposed surfaces or portions ^ 

thereof, causing them to be burnt or oxidized. ' 

It is also important that provision should be mado permitting tho removal for 
repair or replacement of a brush without stoppago of tho machino or interference 
with its capacity or the current transmitted. , . 

23 To accomplish these results each brush or spring is secured in a holder having 

an angle therein, so that the brush or spring may be set to bear obliquely upon 

the commutator, that is, at an angle oilier than a right angle with the ax 8 of the 
emulator. This lioldor is pivoted in an U shaped jaw ■» wnatis 


commutator. This holder is pivoted in an U snapeci jaw in the top of what* 8 
afterwards tho stem or shank of the lioldor. At the pivoted pom 

wsnsftttt 

lowereml of tlm'shank or stem is a recess, into which from below passes the end 
W ^° r ^&«,o commutator are two metallic conducting^e.h fbtmmg one 
terminal of tho exterior circuit. These bats are 01 „ ronvB in their under 
stems or shanks last described and are F° vld8 ^ b » g ^ a[] j ugtablo Bpring 
surface. Upou each of theso bars two, three, or re(;csse j portion upon the 
4(1 scaled commutator brushos are placed by slippii g un |j[ its end takes 

bar, they being then secured thereto by turning tho sot screw until 

Kg.,-1.» »■ > »■ “» 

« "X*. i h . rf. ud -ri» T b '“ l “ 

tho luvention. , , ,, * 

Figure 2 is a side view of ono brush holder; , ,, 

Figure 3 a longitudinal section of part of on ^ machine placed ns usual 

A is the commutator of a dy uau.o or iaa o at its outer 0 nd in bearings O j 

60 at tho end of tho rotating armature B > und 8 “ pp 0 f the armature, but insulated 
a, a, being the strips thereof connected to the cods « “ bars D, D, 

from each other. At a suitablo distance from tbe coimnurere n 








_ Jensen's Improvements in Dynamo-ele ctric Machines, £c. 

aro supported in (but insulated from) supports D 1 , D 1 , (ono of which only is 
shown). 1 

The brush holdors aro mado in two pieces E, F, tho part E being formed with 
an U shnpod recess or jaw at its upper ond, in which takes and in which is 
pivoted the part F. A pin or pivot i passos through the two parts and holds them { 
together. In the lowor portion of tho part F a chamber is formed, in which is 
placed tho spring h, whose inner end is attached to i, tho outer end being fast to the 
wall of tho chamber. Upon tho end of i, outsido of the chamber is a ratchet 
wheel k, a pawl m being arranged upon E to take into tho teeth of k, and hold it 
m a fixed position. In the uppor or free end of F is a chnmbor or recess / for 10 
receiving and holding a brush which is socurcd therein by a set screw e. Upon 
the inner side of E is cut a groove the size of the bar D, in tho under side of which 
is cut a slot, as shown in Figures 2 and 3. 

A series of commutator brush holders thus constructed are placed side by side 
upon the bars D, D, by simply slipping each on to tho bar from tho front, each 1 
being secured thereon by tho set screws d, taking into tho groove in D. 

The use. of a series, ns shown, involves several advantages. Each scries of 
brushes is in metallic contact at tho same timo with the same strip or strips of the 
commutator, hence sparks between tho commutator and brushes are greatly lessened, 
if not entirely obviated, even with a very largo current. If repairs upon or 2( 
replacement of one or more brushes bo necessary tho set scrows d of the defective 
brushes are loosened, and the holders of such defective brushes removed from tho 
bar D without disturbance of the remaining brushes which atTord nmple contact 
surface. 

As before Btated tho ratchet k is upon the pivot i, to which is attached the 2i 
spring h, hence by turning tho ratchet k any desired degree of resilience may ho 
given the spring, which forco is expended in holding tho brushes upon the com¬ 
mutator with a steady and uniform pressure, which may bo varied or regulated by 
means of tho ratchet. This arrangement affords a largo contact surface, while at 
the same time any ono brush may bo removed for repair or replacement without 30 
interference with tho generative capacity of tho machino or disturbance of the 
current, and to it is given tho name “ lurgo current multiplo brushes. 

.pother portion of the Invention relates to tho combination of tho prime motor 
with tho mngneto or dynamo electric machino. 

In using mngneto or dynumo electric machines it is very important that the 35 
armatures should be rotated at an uniform and constant speed, os any variation 
therein immediately manifests itself in the current. As ordinnrily used such 
machines are connected to the prime motor by intermediate gearing, usually belts, 
winch are liable to slip, causing irregularity in the rotation of tho nrmaturo or 
bobbin, every such irregularity affecting tho current, causing the irregularity to be 40 
repeated and shown in tho operation of whatever translating doviccs aro used in 
tho circuit. ° 

To obviate this it is preferable to connect the prime motor and tho generator 
airectly, that is, supposing the prime motor to bo a steam engine, tho pitman rod of 
the engine is connected directly to tho shaft or axlo of tho revolving bobbin, 45 
prcterably by a crank-pin on a disk upon the end of tho bobbin shaft, which disk 
weighted upon the sido opposite to tho crank pin with a weight which counter¬ 
balances the weight of the pin and pitman, so that any jar or irregularity in 
P , ln 8 dead renters is obviated. This arrangoinent is specially needed, os the 
. 8'?° ? 3ed 8 . ud * )e one of very rapid stroke, not loss than four hundred to five 50 
order that tho bobbin may receive its needed high ruto of 
ration. The engine should also bo what may be called a " solf contained engine, 
P r , ov ‘ ded will > a governor aud an automatic variable cut off, which may be 
eb n r,i U j » ~ pon t,ie 8 P° ed becoming too great, the cut-off shall be automatically 
changed to cut off at a less fraction of the stroke, and vice versa. , 65 

is i P „ ®°J!i re0 “ e s P eed °f the engine lessens, the rate of rotation of the bobbin 
a, ana consequently the electro motive force or pressure of tho generated 


Jensen’s Improvements in Dynamo-electric Machines,1T~ 
current drops. If tho steam ongino and generator be so arranged, there is nrovided 
rn^to m m° inCnTd c°o«. ° nUt0mati “"y tho 1“ « «f «>e current 

In manufacturing generators of large capacity, very largo cores and vory largo 
6 castings for polar extensions aro required. These very large parts cosT more 
proportionately than small ones, and are much more difficult to handle, the winding 
of them requiring greater labor and care. Tho greatest effoct upon tho cores is 
given by the coils nearest to it, but in using very large cores some of the coils aro 
necessarily somewhat distant from tho core. With several smaller cores, whose 
10 aggregate of weight is that of ono larger core, a larger surface for tho action of 
coils may bo obtained, and a larger amount of wire used, whoso average distanco 
from the surface of the cores in either case is the same. Generators of very great 
capacity may thoreforo bo profitably constructed of a series (two or more) of coils 
and cores, or field magnets, each set having its own polar extensions, but one 
15 armature or bobbin common to nil being used. 

By such construction, ns before explained, ease and economy of construction are 
secured, tho coilB aro brought on an average nearer the cores, and a greater amount 
of wire may bo profitably used. Moreover, if at any time it is desired to increase 
tho capacity of the generator, it may be dono by adding more field magnets to those 
20 already in tho generator, tho only new pnrt required being a proportionately longer 
bobbin. 

As ensuring compactness and strength, it is preferablo to mount the engine and 
generator upon ono base, on which is secured, upon intermediate supports of a non- j 
magnetic suliBtanco, tho generator, the non-mngnetic supports being necessary to 
25 avoid tho formation of a magnetic circuit outsido of the polar extensions. In order 
to give greater rigidity and needed support to the generator, the series of polar 
extensions are united physically by a braco or union of non-magnetic material, 
which in effect makes the opposite poles one structurally, but preserves them 
separato magnetically. 

30 This is illustrated in Figure 4 of tho Drawings, which represents a prime motor 
and a generator united and constructed, as before set forth. 

L is a suitable base, preferably of cast iron, upon which is secured the individual 
base M of tho steam engine. This base M may bo cast in ono piece with L, or it 
may be mudo separate and properly fastened thereon ; A is the cylinder of the ongirie 
35 provided with tho usual throttle vnlvo a, and with steam chest, &c., not shown in 

1 TtaXton rod B connects to pitman b, which takes on a crank pin on the disc C, 
to which is secured a block or weight which counter balances the weight of the 
crank-pin and the pitman b. The disc C is mounted upon the shaft e, wh eh also 
40 carries the revolving armature or bobbin, and is therefore both the engine and 
bobbin shaft, and maybe termed properly either a bobbin or aupu ■haft 
The engine is provided with a governor G, rotated osusual ham o 10 “ "5 
of tho machinery, and attached to a variable cut off, so as to 
the cut-off reducing or increasing the speed by lengthening or shorten g 
46 proportion of tho stroke during which steam is adimtted. E,E,L, repent 
three scries of field of forco magnets, each series form.ng on inagnot e core^ of 
whose coils are connected by a back ,1000 or . r vo , ke '. f ; A^ no l r xtenskns 

S'UVS" JUT.S. «b., p„i 

vertically. In order then to give necessary ngtdfty, and ensuro^ne p ^ ^ 

between the poles for tho rotation of tho t he bobbin or armature E‘